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Deng Z, Dang Z, Chen T, Ding Z, Zhang Z. The mode detangler. OPTICS LETTERS 2024; 49:5228-5231. [PMID: 39270272 DOI: 10.1364/ol.536665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Accepted: 09/01/2024] [Indexed: 09/15/2024]
Abstract
Astrophotonics aims to transfer photonic technology to the development of compact astronomical instruments. However, light coupling from a multimode fiber, typically adopted in modern observatories, to a single-mode photonic device still poses a challenge. Though a photonic lantern can enable this transition in a low-loss way, it requires that the number of single-mode fibers (SMFs) at the output is the same as the number of guided modes in the multimode fiber, resulting in a cumbersome fan-out of many single-mode devices to be connected. Herein, we invent an active device in a waveguide form called "the mode detangler" (MD). We show that it can adaptively transform a complex light field from a multimode fiber to a single-mode-like spot. In this way, only one single-mode device is required at the end. The path leading to the idea and the theory behind the mode detangling effect is explained, followed by numerical simulations and experimental demonstrations using a few-mode fiber as proof of concept. We believe this device has the potential to address the multimode-to-single-mode conversion challenge in astrophotonics but also sheds light on (de)multiplexing applications regarding spatial mode technology in optical communications.
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2
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Chandrasekharan HK, Barrow P, MacLachlan D, Thomson RR, Donaldson R. Enhancements to quantum communication performance utilizing a prototype photonic lantern and multiplexed single-photon detection. OPTICS LETTERS 2024; 49:5252-5255. [PMID: 39270278 DOI: 10.1364/ol.533488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 08/23/2024] [Indexed: 09/15/2024]
Abstract
The optical interfacing between a free-space channel and single-photon detectors (SPDs) can greatly impact the inherent performance of a free-space quantum key distribution receiver. Direct coupling to detectors creates engineering challenges, and a single-mode fiber requires adaptive optics. Using a multimode fiber (MMF) is common; however, larger core diameters limit the achievable bandwidth. We demonstrate a prototype multimode fiber-based photonic lantern that allows us to retain the benefits of the large multimode coupling while transitioning to multiple, less multimodal fibers, reducing bandwidth limitation.
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3
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Rezaei-Latifi A. Designing an imaging spectrometer with high resolution using manufacturable gradient-index (MGRIN) lenses with a linear distribution of refractive index. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:083301. [PMID: 39101785 DOI: 10.1063/5.0218476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 07/19/2024] [Indexed: 08/06/2024]
Abstract
In this work, an imaging spectrometer with a diffraction-limited resolution of 0.043 nm is designed by using two manufacturable gradient-index (MGRIN) lenses with a linear refractive index distribution to suppress the aberrations. The MGRIN lenses are made from a combination of two separate base materials that their refractive indices are determined by the fractional composition of each base material at any point. The volume fraction of each base material in both lenses changes linearly from the front edge to the rear vertex of the lens. The input light to the spectrometer originates from a single-mode fiber with a core diameter of 9 μm and a numerical aperture of 0.1. The parallel rays after passing through the collimator are diffracted by a diffraction grating with a number of grooves of 1200 g/mm. The criteria determining the quality of the image show that the aberrations of the image have been optimally controlled. Comparing the results of this design with some similar studies done by other researchers shows that the root-mean-square radius of the spot diagram and Airy disk radius are significantly smaller than those designs. In addition, the modulation transfer function diagram has a better fit with the diffraction limit curve. These results make our proposed spectrometer have a stronger resolution than those in previous studies.
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Affiliation(s)
- Ali Rezaei-Latifi
- Physics Department, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Iran
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Zhang Q, Charania S, Rothe S, Koukourakis N, Neumann N, Plettemeier D, Czarske JW. Multimode Optical Interconnects on Silicon Interposer Enable Confidential Hardware-to-Hardware Communication. SENSORS (BASEL, SWITZERLAND) 2023; 23:6076. [PMID: 37447925 PMCID: PMC10346219 DOI: 10.3390/s23136076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Following Moore's law, the density of integrated circuits is increasing in all dimensions, for instance, in 3D stacked chip networks. Amongst other electro-optic solutions, multimode optical interconnects on a silicon interposer promise to enable high throughput for modern hardware platforms in a restricted space. Such integrated architectures require confidential communication between multiple chips as a key factor for high-performance infrastructures in the 5G era and beyond. Physical layer security is an approach providing information theoretic security among network participants, exploiting the uniqueness of the data channel. We experimentally project orthogonal and non-orthogonal symbols through 380 μm long multimode on-chip interconnects by wavefront shaping. These interconnects are investigated for their uniqueness by repeating these experiments across multiple channels and samples. We show that the detected speckle patterns resulting from modal crosstalk can be recognized by training a deep neural network, which is used to transform these patterns into a corresponding readable output. The results showcase the feasibility of applying physical layer security to multimode interconnects on silicon interposers for confidential optical 3D chip networks.
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Affiliation(s)
- Qian Zhang
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany; (S.R.); (N.K.); (J.W.C.)
| | - Sujay Charania
- Chair of Radio Frequency and Photonics Engineering, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany;
| | - Stefan Rothe
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany; (S.R.); (N.K.); (J.W.C.)
| | - Nektarios Koukourakis
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany; (S.R.); (N.K.); (J.W.C.)
| | - Niels Neumann
- Institute for Electrical Information Technology, TU Clausthal, 38678 Clausthal-Zellerfeld, Germany;
| | - Dirk Plettemeier
- Chair of Radio Frequency and Photonics Engineering, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany;
| | - Juergen W. Czarske
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany; (S.R.); (N.K.); (J.W.C.)
- Institute of Applied Physics, School of Science, TU Dresden, 01069 Dresden, Germany
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5
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Trinh PV, Kolev DR, Shiratama K, Carrasco-Casado A, Munemasa Y, Yamazoe H, Komatsu H, Kamata T, Nakao T, Ohta S, Iwamoto K, Fujiwara M, Tsuji H, Toyoshima M. Experimental verification of fiber coupling characteristics for FSO downlinks from the International Space Station. OPTICS EXPRESS 2023; 31:9081-9097. [PMID: 36860008 DOI: 10.1364/oe.484512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Free-space optical (FSO) systems are compulsory to realize high capacity and interference-free communication links from low-Earth orbit (LEO) satellite constellations as well as spacecraft and space stations to the Earth. To be integrated with high-capacity ground networks, the collected portion of the incident beam should be coupled into an optical fiber. To accurately evaluate the signal-to-noise ratio (SNR) and bit-error rate (BER) performance metrics, the probability density function (PDF) of fiber coupling efficiency (CE) must be determined. Previous studies have experimentally verified the CE PDF for a single-mode fiber, however, there is no such investigation for the CE PDF of a multi-mode fiber (MMF) in a LEO-to-ground FSO downlink. In this paper, for the first time, the CE PDF for a 200-μm MMF is experimentally investigated using data from an FSO downlink from the Small Optical Link for International Space Station (SOLISS) terminal to a 40-cm sub-aperture optical ground station (OGS) supported by a fine-tracking system. An average CE of 5.45 dB was also achieved given that the alignment between SOLISS and OGS was not optimal. In addition, using the angle-of-arrival (AoA) and received power data, the statistical characteristics such as channel coherence time, power spectral density, spectrogram, and PDFs of AoA, beam misalignments, and atmospheric turbulence-induced fluctuations are revealed and compared with the state-of-the-art theoretical background.
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6
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Zhan J, Zhang Y, Hsu WL, Veilleux S, Dagenais M. Design and implementation of a Si 3N 4 three-stigmatic-point arrayed waveguide grating with a resolving power over 17,000. OPTICS EXPRESS 2023; 31:6389-6400. [PMID: 36823896 DOI: 10.1364/oe.480823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
To provide a solution to the issue of the non-flat focal surface in traditional Rowland AWGs, we have designed and implemented a Si3N4 three-stigmatic-point arrayed waveguide grating (TSP AWG) with three inputs, and a spectral resolving power over 17,000 has been achieved experimentally. The flat focal surface of this AWG can accommodate a butt-coupled detector array positioned at the output facet without any reduction of the resolving power of the edge channels. Therefore, it is particularly advantageous to some astronomical applications which require an AWG as a light-dispersing component to obtain a complete 2D spectrum. As a proof-of-concept for next generation devices, the multi-input aspect of the design accommodates multiple single-mode fibers coming into the AWG. In addition, because the device is implemented on a high-index-contrast platform (Si3N4/SiO2), a compact size of ∼9.3 × 9.3 mm2 is achieved.
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7
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Tian P, Bi W, Jin W, Ke S, Xia X, Fu G, Fu X. All-fiber LP 01-LP 11 ultra-broadband mode converters based on T-superimposed long period gratings in PCF. OPTICS EXPRESS 2022; 30:42046-42056. [PMID: 36366666 DOI: 10.1364/oe.471026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
In order to cover the bandwidth of optical fiber communication, a LP01-LP11 ultra-broadband mode converter based on triple superimposed long period grating in PCF is proposed and demonstrated. The transmission spectra of the D-SLPG with gratings pitches and the T-SLPG were simulated and analyzed. The simulation results on the D-SLPG indicate that the 3 dB bandwidth of the D-SLPG is more than 1.5 times than the 3 dB bandwidth of the independent LPG and the 3 dB bandwidth of T-SLPG approaches 2.6 times as much as the independent LPG. In the experiment, the mode converter based on PCF-T-SLPG covers the wavelength of S + C + L with 3 dB bandwidth of 121 nm from 1498 nm to 1619 nm. In addition, the mode converter based on PCF-T-SLPG can accomplish ultra-broadband transmission in any wavelength by adjusting the period of gratings.
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Mathew NM, Grüner-Nielsen L, Wang Z, Rishøj LS, Rottwitt K. Broadband air-clad LP 02 mode converter using a tapered mode transition. OPTICS LETTERS 2022; 47:38-41. [PMID: 34951877 DOI: 10.1364/ol.446055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/21/2021] [Indexed: 06/14/2023]
Abstract
Higher-order mode converters that work over a broad wavelength range are needed for various applications. A new, to the best of our knowledge, simple and cost-effective LP02 mode converter is fabricated by tapering a bundle of single-mode fibers. The device excites the LP02 mode in a four-mode step index fiber with a mode purity higher than 10 dB. The polarization-dependent cross talk of the device is measured using the S2 technique. The LP02 mode selectivity of the device is measured over the entire C and L bands by selectively launching different modes into the device using a spatial light modulator.
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9
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Mohsen H Mahmoud M, Younis BM, Areed NFF, Hameed MFO, Obayya SSA. Tunable liquid crystal asymmetric dual-core photonic crystal fiber mode converter. APPLIED OPTICS 2021; 60:7671-7677. [PMID: 34613237 DOI: 10.1364/ao.432430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
In this study, a compact mode converter based on an asymmetric dual-core photonic crystal fiber (ADC-PCF) infiltrated with nematic liquid crystal (NLC) is reported. The full vectorial finite difference method is used to compute the modal characteristics of the studied transverse magnetic (TM) mode. In this investigation, the geometrical and material parameters of the proposed mode converter are studied to achieve high wavelength selectivity with a compact device length. The proposed mode converter has a compact device length of 403.6 µm at λ=1.3µm. In addition, the reported device is simulated under different temperature levels from 15°C to 45°C to show the thermal tunability. Therefore, the proposed design can be used efficiently in integrated photonic circuits.
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10
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Diab M, Tripathi A, Davenport J, Dinkelaker AN, Madhav K, Roth MM. Simulations of mode-selective photonic lanterns for efficient coupling of starlight into the single-mode regime. APPLIED OPTICS 2021; 60:D9-D14. [PMID: 34263824 DOI: 10.1364/ao.421799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/11/2021] [Indexed: 06/13/2023]
Abstract
In ground-based astronomy, starlight distorted by the atmosphere couples poorly into single-mode waveguides, but a correction by adaptive optics, even if only partial, can boost coupling into the few-mode regime, allowing the use of photonic lanterns to convert into multiple single-mode beams. Corrected wavefronts result in focal patterns that couple mostly with circularly symmetric waveguide modes. A mode-selective photonic lantern is hence proposed to convert multimode light into a subset of single-mode waveguides of the standard photonic lantern, thereby reducing the required number of outputs. We ran simulations to show that only two out of the six waveguides of a 1×6 photonic lantern carry >95% of the coupled light to the outputs at D/r0<10 if the wavefront is partially corrected and the photonic lantern is made mode selective.
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11
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Robertson G, Ellis S, Yu Q, Bland-Hawthorn J, Betters C, Roth M, Leon-Saval S. Seeking celestial positronium with an OH-suppressed diffraction-limited spectrograph. APPLIED OPTICS 2021; 60:D122-D128. [PMID: 34263851 DOI: 10.1364/ao.421560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/13/2021] [Indexed: 06/13/2023]
Abstract
Celestially, positronium (Ps) has been observed only through gamma-ray emission produced by its annihilation. However, in its triplet state, a Ps atom has a mean lifetime long enough for electronic transitions to occur between quantum states. This produces a recombination spectrum observable in principle at near IR wavelengths, where angular resolution greatly exceeding that of the gamma-ray observations is possible. However, the background in the near IR is dominated by extremely bright atmospheric hydroxyl (OH) emission lines. In this paper, we present the design of a diffraction-limited spectroscopic system using novel photonic components-a photonic lantern, OH fiber Bragg grating filters, and a photonic TIGER 2D pseudo-slit-to observe the Ps Balmer alpha line at 1.3122 µm for the first time, to our knowledge.
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12
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Cruz-Delgado D, Alvarado-Zacarias JC, Cooper MA, Wittek S, Dobias C, Martinez-Mercado J, Antonio-Lopez JE, Fontaine NK, Amezcua-Correa R. Photonic lantern tip/tilt detector for adaptive optics systems. OPTICS LETTERS 2021; 46:3292-3295. [PMID: 34197439 DOI: 10.1364/ol.430761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
In this work, we demonstrate a four-core multicore fiber photonic lantern tip/tilt wavefront sensor. To diagnose the low-order Zernike aberrations, we exploit the ability of the photonic lantern to encode the characteristics of a complex incoming beam at the multimode facet of the sensor to intensity distributions at the multicore fiber output. Here, we provide a comprehensive numerical analysis capable of predicting the performance of fabricated devices and experimentally demonstrate the concept. Two receiver architectures are implemented to discern tip/tilt information by (i) imaging the four-core fiber facet on a 2D detector and (ii) direct power measurement of the single mode outputs using a multicore fiber multiplexer and photodetectors. For both receiver schemes, an angular detection window of ∼0.4∘ at 1064 nm can be achieved. Our results are expected to further facilitate the development of intensity-based fiber wavefront sensors for adaptive optics systems.
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13
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Liu P, Czaplewski DA, Ellis S, Kehoe R, Kuehn K, Spinka HM, Stern NP, Underwood DG, Kuhlmann S. Optimizing photonic ring-resonator filters for OH-suppressed near-infrared astronomy. APPLIED OPTICS 2021; 60:3865-3873. [PMID: 33983324 DOI: 10.1364/ao.421383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Near-infrared wavelength observations are crucial for understanding numerous fields of astrophysics, such as supernova cosmology and positronium annihilation detection. However, current ground-based observations suffer from an enormous background due to OH emission in the upper atmosphere. One promising way to solve this problem is to use ring-resonator filters to suppress OH emission lines. In this work, we discuss our optimization of ring-resonator filter performance from five perspectives: resonance wavelength matching, polarization-independent operation, low insertion loss, low-loss coupling to astronomical instruments, and broadband operation. In the end, we discuss next steps needed for reliable supernova and positronium observations, thus providing a roadmap for future advances in near-infrared astronomy.
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14
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Qiu T, Yang S, Wang A. Experimental investigation of point-by-point off-axis Bragg gratings inscribed by a femtosecond laser in few-mode fibers. OPTICS EXPRESS 2020; 28:37553-37565. [PMID: 33379588 DOI: 10.1364/oe.409228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Off-axis Bragg gratings with varied horizontal and vertical distances off the center in a step-index two-mode fiber were fabricated by 800 nm infrared-femtosecond laser pulses through a point-by-point technique. In this article, we experimentally investigate these gratings via measuring the transmitted power and the reflected intensity profiles under different input polarization, with multiple characteristics reported for the first time to the best of our knowledge. To highlight, we find that the birefringence induced to the LP01 reaches its maximum magnitude at an intermediate offset, followed by the fast and slow axes switching at a further slightly increased offset. We also show that the peak reflectivity of the LP11 exhibits strong polarization dependence, with the much stronger peak reflectivity constantly corresponding to the polarization perpendicular to the damage-point-to-center line, whereas the peak reflectivity of the LP01 has almost no polarization dependence. Moreover, we report that the reflected mode patterns of the cross-coupling of the LP01 and LP11 are linked to the direction of linear polarization, through which one can selectively excite an arbitrarily oriented LP11 by merely altering the polarization.
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15
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Optical and mechanical properties of self-written polymer waveguide between single mode optical fibers using UV photocurable monomer system. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.109950] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Arikawa M, Ito T. Performance of mode diversity reception of a polarization-division-multiplexed signal for free-space optical communication under atmospheric turbulence. OPTICS EXPRESS 2018; 26:28263-28276. [PMID: 30470001 DOI: 10.1364/oe.26.028263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/17/2018] [Indexed: 06/09/2023]
Abstract
We investigated the performance of mode diversity reception of a polarization-division-multiplexed (PDM) signal with few-mode-fiber (FMF) coupling for high-speed free-space optical communications under atmospheric turbulence. Optical propagation through eigenmodes of a FMF yields coupling between different linearly polarized (LP) modes in orthogonal polarizations, which causes power imbalance and loss of the orthogonality of multiplexed signals within each individual LP mode. Due to this phenomenon, the architecture of mode diversity combining affects the receiver performance. We numerically simulated the power fluctuation coupled to each LP mode after atmospheric propagation and FMF propagation in the condition of an optical downlink from a low-Earth-orbital satellite to the ground. We found that full receiver-side multiple-input multiple-output (Rx-MIMO) architecture in three-mode diversity reception improved the performance by 5 dB compared with selection combining (SC) of signals decoded individually in LP modes, and that it mitigated the required transmitted power by 6 dB compared with reception with single mode fiber (SMF) coupling. We also experimentally confirmed in three-mode diversity reception of a 128 Gb/s PDM-quadrature phase-shift keying with a diffuser plate as a turbulence emulator, that full Rx-MIMO with adaptive filters could work under severe fading and that it outperformed SC.
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17
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Shen L, Gan L, Huo L, Yang C, Tong W, Fu S, Tang M, Liu D. Design of highly mode group selective photonic lanterns with geometric optimization. APPLIED OPTICS 2018; 57:7065-7069. [PMID: 30129600 DOI: 10.1364/ao.57.007065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/25/2018] [Indexed: 06/08/2023]
Abstract
Highly mode group selective photonic lanterns (PLs) are desired for mode-division multiplexing transmission systems. Usually, mode selectivity is achieved by using input fibers with different core diameters or refractive indices to break degeneracy between mode groups. We demonstrate that mode group selectivity can be greatly improved by optimizing core geometry of PLs. For three-mode PLs with optimized core geometry, based on beam propagation method (BPM) simulation results, mode selectivity is improved from 23.8 dB to 43.9 dB for LP01 mode, and mode selectivity of LP11 mode is improved from 26.8 dB to 45.5 dB. The reason is the optimized core geometry can significantly slow down the changing of mode profile along the taper of the PL; thus adiabatic tapering requirement can be greatly alleviated. It can also be observed that the simulation results by the BPM are in good agreement with calculation of coupled-mode theory.
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18
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Velázquez-Benítez AM, Antonio-López JE, Alvarado-Zacarías JC, Fontaine NK, Ryf R, Chen H, Hernández-Cordero J, Sillard P, Okonkwo C, Leon-Saval SG, Amezcua-Correa R. Scaling photonic lanterns for space-division multiplexing. Sci Rep 2018; 8:8897. [PMID: 29891993 PMCID: PMC5995907 DOI: 10.1038/s41598-018-27072-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/09/2018] [Indexed: 11/18/2022] Open
Abstract
We present a new technique allowing the fabrication of large modal count photonic lanterns for space-division multiplexing applications. We demonstrate mode-selective photonic lanterns supporting 10 and 15 spatial channels by using graded-index fibres and microstructured templates. These templates are a versatile approach to position the graded-index fibres in the required geometry for efficient mode sampling and conversion. Thus, providing an effective scalable method for large number of spatial modes in a repeatable manner. Further, we demonstrate the efficiency and functionality of our photonic lanterns for optical communications. Our results show low insertion and mode dependent losses, as well as enhanced mode selectivity when spliced to few mode transmission fibres. These photonic lantern mode multiplexers are an enabling technology for future ultra-high capacity optical transmission systems.
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Affiliation(s)
- Amado M Velázquez-Benítez
- CREOL, The College of Optics & Photonics, the University of Central Florida, Orlando, Florida, 32816-2700, USA. .,Bell Laboratories/Alcatel-Lucent, 791 Holmdel Rd., Holmdel, New Jersey, 07733, USA. .,Instituto de Investigaciones en Materiales, UNAM, Cd Universitaria, Ciudad de México, 04510, Mexico. .,Instituto de Ciencias Aplicadas y Tecnología, UNAM, Cd. Universitaria, Mexico City, 04510, Mexico.
| | - J Enrique Antonio-López
- CREOL, The College of Optics & Photonics, the University of Central Florida, Orlando, Florida, 32816-2700, USA
| | - Juan C Alvarado-Zacarías
- CREOL, The College of Optics & Photonics, the University of Central Florida, Orlando, Florida, 32816-2700, USA
| | - Nicolas K Fontaine
- Bell Laboratories/Alcatel-Lucent, 791 Holmdel Rd., Holmdel, New Jersey, 07733, USA
| | - Roland Ryf
- Bell Laboratories/Alcatel-Lucent, 791 Holmdel Rd., Holmdel, New Jersey, 07733, USA
| | - Haoshuo Chen
- Bell Laboratories/Alcatel-Lucent, 791 Holmdel Rd., Holmdel, New Jersey, 07733, USA
| | - Juan Hernández-Cordero
- Instituto de Investigaciones en Materiales, UNAM, Cd Universitaria, Ciudad de México, 04510, Mexico
| | - Pierre Sillard
- Prysmian Group, Parc des Industries Artois Flandres, 644 boulevard Est, Billy Berclau, 62092, Haisnes Cedex, France
| | - Chigo Okonkwo
- Institute for Photonic Integration, Flux, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Sergio G Leon-Saval
- Institute of Photonics and Optical Science, School of Physics, The University of Sydney, New South Wales, 2006, Australia
| | - Rodrigo Amezcua-Correa
- CREOL, The College of Optics & Photonics, the University of Central Florida, Orlando, Florida, 32816-2700, USA.
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Montoya J, Hwang C, Martz D, Aleshire C, Fan TY, Ripin DJ. Photonic lantern kW-class fiber amplifier. OPTICS EXPRESS 2017; 25:27543-27550. [PMID: 29092225 DOI: 10.1364/oe.25.027543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 10/16/2017] [Indexed: 06/07/2023]
Abstract
Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control and a photonic lantern front end was achieved. An array of three single-mode fiber inputs was used to adaptively inject the appropriate superposition of input modes in a three-mode gain fiber to achieve the desired mode at the output. Mode fluctuations at high power were compensated by adjusting the relative phase, amplitude, and polarization of the single-mode fiber inputs. The outlook for further power scaling and adaptive-optic compensation is described.
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20
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Gatkine P, Veilleux S, Hu Y, Bland-Hawthorn J, Dagenais M. Arrayed waveguide grating spectrometers for astronomical applications: new results. OPTICS EXPRESS 2017; 25:17918-17935. [PMID: 28789281 DOI: 10.1364/oe.25.017918] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
One promising application of photonics to astronomical instrumentation is the miniaturization of near-infrared (NIR) spectrometers for large ground- and space-based astronomical telescopes. Here we present new results from our effort to fabricate arrayed waveguide grating (AWG) spectrometers for astronomical applications entirely in-house. Our latest devices have a peak overall of ∼23%, a spectral resolving power (λ/δλ) of ~1300, and cover the entire H band (1450-1650 nm) for Transverse Electric (TE) polarization. These AWGs use a silica-on-silicon platform with a very thin layer of Si3N4 as the core of the waveguides. They have a free spectral range of ~10 nm at a of ~1600 about wavelength nm and a contrast ratio or crosstalk of 2% (-17 dB). Various practical aspects of implementing AWGs as astronomical spectrographs are discussed, including the coupling of the light between the fibers and AWGs, high-temperature annealing to improve the throughput of the devices at ~1500 nm, cleaving at the output focal plane of the AWG to provide continuous wavelength coverage, and a novel algorithm to make the devices polarization insensitive over a broad band. These milestones will guide the development of the next generation of AWGs with wider free spectral range and higher resolving power and throughput.
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Leon-Saval SG, Betters CH, Salazar-Gil JR, Min SS, Gris-Sanchez I, Birks TA, Lawrence J, Haynes R, Haynes D, Roth M, Veilleux S, Bland-Hawthorn J. Divide and conquer: an efficient solution to highly multimoded photonic lanterns from multicore fibres. OPTICS EXPRESS 2017; 25:17530-17540. [PMID: 28789244 DOI: 10.1364/oe.25.017530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/07/2017] [Indexed: 06/07/2023]
Abstract
Photonic lanterns typically allow for single-mode action in a multimode fibre. Since their invention over a decade ago for applications in astrophotonics, they have found important uses in diverse fields of applied science. To date, large aperture highly-mulitmoded to single-mode lanterns have been difficult as fabrication techniques are not practical for mass replication. Here as a proof of concept, we demonstrate three different devices based on multicore fibre photonic lanterns with: 100µm core diameters; NAs = 0.16 and 0.15; and requiring 259 single-mode core system, specifically 7 multicore fibres each with 37 cores, instead of 259 individual single-mode fibres. The average insertion loss excluding coupling efficiencies is only 0.4dB (>91% transmission). This concept has numerous advantages, in particular, (i) it is a direct scaleable solution, (ii) eases imprinting of photonic functions, e.g. fibre Bragg gratings; and (iii) new approach for large-area optical fibre slicers for future large-aperture telescopes.
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Lei Y, Li J, Wu R, Fan Y, Fu S, Yin F, Dai Y, Xu K. Experimental study on the statistic characteristics of a 3x3 RF MIMO channel over a single conventional multimode fiber. OPTICS LETTERS 2017; 42:2217-2220. [PMID: 28569885 DOI: 10.1364/ol.42.002217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/15/2017] [Indexed: 06/07/2023]
Abstract
Based on the observed random fluctuation phenomenon of speckle pattern across multimode fiber (MMF) facet and received optical power distribution across three output ports, we experimentally investigate the statistic characteristics of a 3×3 radio frequency multiple-input multiple-output (MIMO) channel enabled by mode division multiplexing in a conventional 50 µm MMF using non-mode-selective three-dimensional waveguide photonic lanterns as mode multiplexer and demultiplexer. The impacts of mode coupling on the MIMO channel coefficients, channel matrix, and channel capacity have been analyzed over different fiber lengths. The results indicate that spatial multiplexing benefits from the greater fiber length with stronger mode coupling, despite a higher optical loss.
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Function of second cladding layer in hollow core tube lattice fibers. Sci Rep 2017; 7:1618. [PMID: 28487540 PMCID: PMC5431655 DOI: 10.1038/s41598-017-01839-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/04/2017] [Indexed: 12/02/2022] Open
Abstract
Modes attenuation of the tube lattice fiber (TLF) is characterized by D/λ, where D is the core diameter and λ is the wavelength. Hence, the TLF is structured with a large core to ensure a low attenuation loss. A small core, on the other hand, facilitates the gas-filled TLF applications, but at the expense of the increased mode attenuation. We show that adding a second cladding layer to the conventional one layer TLF (1TLF) can resolve the contradicting requirements. The mode attenuation of TLF with two cladding layers (2TLF) is less influenced by the D/λ value as compared to 1TLF, thus realizing a low loss small core TLF. Furthermore, we found that adding the second layer brings another advantage to a bending performance. With a determined core size, D, a 1TLF with smaller capillary hole size, d, experiences less bending loss. However, the reduced d increases the confinement loss that counteracts the bending loss improvement. This confliction is substantially alleviated in 2TLF thanks to the second cladding layer. Theoretical investigations and experimental demonstrations are presented to evidence the important role of the second cladding ring in the TLF, which has been overlooked in prior studies.
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Chandrasekharan HK, Izdebski F, Gris-Sánchez I, Krstajić N, Walker R, Bridle HL, Dalgarno PA, MacPherson WN, Henderson RK, Birks TA, Thomson RR. Multiplexed single-mode wavelength-to-time mapping of multimode light. Nat Commun 2017; 8:14080. [PMID: 28120822 PMCID: PMC5288496 DOI: 10.1038/ncomms14080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 11/25/2016] [Indexed: 11/09/2022] Open
Abstract
When an optical pulse propagates along an optical fibre, different wavelengths travel at different group velocities. As a result, wavelength information is converted into arrival-time information, a process known as wavelength-to-time mapping. This phenomenon is most cleanly observed using a single-mode fibre transmission line, where spatial mode dispersion is not present, but the use of such fibres restricts possible applications. Here we demonstrate that photonic lanterns based on tapered single-mode multicore fibres provide an efficient way to couple multimode light to an array of single-photon avalanche detectors, each of which has its own time-to-digital converter for time-correlated single-photon counting. Exploiting this capability, we demonstrate the multiplexed single-mode wavelength-to-time mapping of multimode light using a multicore fibre photonic lantern with 121 single-mode cores, coupled to 121 detectors on a 32 × 32 detector array. This work paves the way to efficient multimode wavelength-to-time mapping systems with the spectral performance of single-mode systems. Photonic lanterns are made by merging several single-mode cores into one multimode core. Here, the authors show this type of structure can both perform wavelength-to-time mapping of multimode states of light and couple such light to an array of single-photon avalanche detectors.
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Affiliation(s)
- Harikumar K Chandrasekharan
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.,Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Frauke Izdebski
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | | | - Nikola Krstajić
- Institute for Integrated Micro and Nano Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Richard Walker
- Institute for Integrated Micro and Nano Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Helen L Bridle
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Paul A Dalgarno
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - William N MacPherson
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Robert K Henderson
- Institute for Integrated Micro and Nano Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Tim A Birks
- Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Robert R Thomson
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
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Lei Y, Li J, Fan Y, Yu D, Fu S, Yin F, Dai Y, Xu K. Space-division-multiplexed transmission of 3x3 multiple-input multiple-output wireless signals over conventional graded-index multimode fiber. OPTICS EXPRESS 2016; 24:28372-28382. [PMID: 27958547 DOI: 10.1364/oe.24.028372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, we experimentally demonstrate space-division-multiplexed (SDM) transmission of IEEE 802.11ac-compliant 3-spatial-stream WLAN signals over 3 spatial modes of conventional 50um graded-index (GI) multimode fiber (MMF) employing non-mode-selective 3D-waveguide photonic lantern. Two kinds of scenarios, including fiber-only transmission and fiber-wireless hybrid transmission, were investigated by measuring error vector magnitude (EVM) performance for each stream and condition number (CN) of the channel matrix. The experimental results show that, SDM-based MMF link could offer a CN< 20dB well-conditioned MIMO channel over up to 1km fiber length within 0-6GHz, achieving as low as 2.38%, 2.97% and 2.11% EVM performance for 1km MMF link at 2.4GHz, 5.8GHz, and 200m MMF link followed by 1m air distance at 2.7GHz, respectively. These results indicate the possibility to distribute wireless MIMO signals over existing in-building commercially-available MMFs with enormous cost-saving.
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Lopez-Galmiche G, Sanjabi Eznaveh Z, Antonio-Lopez JE, Velazquez Benitez AM, Rodriguez Asomoza J, Sanchez Mondragon JJ, Gonnet C, Sillard P, Li G, Schülzgen A, Okonkwo CM, Amezcua Correa R. Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control. OPTICS LETTERS 2016; 41:2588-2591. [PMID: 27244421 DOI: 10.1364/ol.41.002588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to ∼6.2 dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of <1 dB between all modes and signal gains of ∼16 dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated.
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27
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Wittek S, Bustos Ramirez R, Alvarado Zacarias J, Sanjabi Eznaveh Z, Bradford J, Lopez Galmiche G, Zhang D, Zhu W, Antonio-Lopez J, Shah L, Amezcua Correa R. Mode-selective amplification in a large mode area Yb-doped fiber using a photonic lantern. OPTICS LETTERS 2016; 41:2157-2160. [PMID: 27176951 DOI: 10.1364/ol.41.002157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate selective spatial mode amplification in a few mode, double-clad Yb-doped large mode area (LMA) fiber, utilizing an all-fiber photonic lantern. Amplification to multi-watt output power is achieved while preserving high spatial mode selectivity. We observe gain values of over 12 dB for all modes: LP01, LP11a, and LP11b, when amplified individually. Additionally, we investigate the simultaneous amplification of LP01+LP11a and LP11a+LP11b, and the resultant mode competition. The proposed architecture allows for the reconfigurable excitation of spatial modes in the LMA fiber amplifiers, and represents a promising method that could enable dynamic spatial mode control in high power fiber lasers.
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28
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Lindley EY, Min SS, Leon-Saval SG, Cvetojevic N, Lawrence J, Ellis SC, Bland-Hawthorn J. Writing Bragg Gratings in Multicore Fibers. J Vis Exp 2016. [PMID: 27167576 DOI: 10.3791/53326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong suppression at a single wavelength requires that all cores have matching transmission profiles. These gratings cannot be inscribed using the same method as for single-core fibers because the curved surface of the cladding acts as a lens, focusing the incoming UV laser beam and causing variations in exposure between cores. Therefore we use an additional optical element to ensure that the beam shape does not change while passing through the cross-section of the multicore fiber. This consists of a glass capillary tube which has been polished flat on one side, which is then placed over the section of the fiber to be inscribed. The laser beam enters the fiber through the flat surface of the capillary tube and hence maintains its original dimensions. This paper demonstrates the improvements in core-to-core uniformity for a 7-core fiber using this method. The technique can be generalized to larger multicore fibers.
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Affiliation(s)
- Emma Y Lindley
- Sydney Institute for Astronomy, School of Physics, University of Sydney;
| | - Seong-Sik Min
- Sydney Institute for Astronomy, School of Physics, University of Sydney; Institute of Photonics and Optical Science, School of Physics, University of Sydney
| | - Sergio G Leon-Saval
- Sydney Institute for Astronomy, School of Physics, University of Sydney; Institute of Photonics and Optical Science, School of Physics, University of Sydney
| | - Nick Cvetojevic
- Sydney Institute for Astronomy, School of Physics, University of Sydney; Institute of Photonics and Optical Science, School of Physics, University of Sydney; Center for Ultrahigh Bandwidth Devices for Optical Systems, School of Physics, University of Sydney; Australian Astronomical Observatory
| | | | - Simon C Ellis
- Sydney Institute for Astronomy, School of Physics, University of Sydney; Australian Astronomical Observatory
| | - Joss Bland-Hawthorn
- Sydney Institute for Astronomy, School of Physics, University of Sydney; Institute of Photonics and Optical Science, School of Physics, University of Sydney
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Huang X, Qi W, Ho D, Yong KT, Luan F, Yoo S. Hollow core anti-resonant fiber with split cladding. OPTICS EXPRESS 2016; 24:7670-7678. [PMID: 27137053 DOI: 10.1364/oe.24.007670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An improved design for hollow core anti-resonant fibers (HAFs) is presented. A split cladding structure is introduced to reduce the fabrication distortion within design tolerance. We use numerical simulations to compare the Kagome fibers (KFs) and the proposed split cladding fibers (SCFs) over two normalized transmission bands. It reveals that SCFs are able to maintain the desired round shape of silica cladding walls, hence improving the confinement loss (CL) compared to the KF and is comparable to that of the nested antiresonant nodeless fiber (NANF) with the same core size. In addition, the SCF allows stacking multiple layers of cladding rings to control the CL. The influences of the number of cladding layers and the cladding gap width on the CL of the SCFs have been studied. SCF with three cladding rings is fabricated by the stack-and-draw technique. A measured attenuation spectrum matches well with the calculation prediction. The measured near field mode patterns also prove the feasibility of our fiber design.
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Montoya J, Aleshire C, Hwang C, Fontaine NK, Velázquez-Benítez A, Martz DH, Fan TY, Ripin D. Photonic lantern adaptive spatial mode control in LMA fiber amplifiers. OPTICS EXPRESS 2016; 24:3405-3413. [PMID: 26906999 DOI: 10.1364/oe.24.003405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate adaptive-spatial mode control (ASMC) in few-moded double-clad large mode area (LMA) fiber amplifiers by using an all-fiber-based photonic lantern. Three single-mode fiber inputs are used to adaptively inject the appropriate superposition of input modes in a multimode gain fiber to achieve the desired mode at the output. By actively adjusting the relative phase of the single-mode inputs, near-unity coherent combination resulting in a single fundamental mode at the output is achieved.
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31
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Park KJ, Song KY, Kim YK, Lee JH, Kim BY. Broadband mode division multiplexer using all-fiber mode selective couplers. OPTICS EXPRESS 2016; 24:3543-3549. [PMID: 26907011 DOI: 10.1364/oe.24.003543] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report an all-fiber mode division multiplexer formed with cascaded mode selective couplers with significantly broadened bandwidth potentially spanning S, C and L band. This was achieved by matching the effective refractive indices over a wide wavelength range for the few mode fiber and the single mode fiber used in the coupler. The multiplexer provides high coupling efficiency (>55% for the worst case) for the 4 spatial modes over the entire wavelength range of 1515-1590 nm. The all-fiber construction provides mechanical stability. Experimental results for the coupling efficiency and the mode extinction ratio for each spatial mode are presented along with the far field radiation patterns.
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32
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Awad E. Multicore optical fiber Y-splitter. OPTICS EXPRESS 2015; 23:25661-25674. [PMID: 26480082 DOI: 10.1364/oe.23.025661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In future high capacity multicore optical fiber (MCF) networks, signal-processing devices should be able to manipulate data without sacrificing network capacity or MCFs advantages. Thus, it is crucial to have high performance novel devices that can be connected directly to MCFs without conversion to conventional single-core fibers. In this work, a novel Y-splitter for multicore optical fibers is proposed and numerically demonstrated for the first time. The splitter can directly split the power of input MCF cores by 50/50 splitting-ratio into two output MCFs cores. The splitter principle of operation mainly depends on novel double-hump graded-index (DHGI) profile that can space-division split (SDS) optical power by half. Both finite-difference-time-domain and eigenmode-expansion simulations are performed to design, verify, and characterize performance of Y-splitter. It shows wideband operation over the S, C, L, U-bands with polarization insensitivity. It also demonstrates high performance with reasonable insertion-loss, in addition to very low excess-loss and return-loss. Moreover, the splitter shows good performance tolerance to both MCF and design parameters variations.
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33
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Pelegrina-Bonilla G, Hausmann K, Sayinc H, Morgner U, Neumann J, Kracht D. Analysis of the modal evolution in fused-type mode-selective fiber couplers. OPTICS EXPRESS 2015; 23:22977-22990. [PMID: 26368403 DOI: 10.1364/oe.23.022977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Fused-type mode-selective fiber couplers exciting the LP(11) mode are fabricated by well-defined fiber cladding reduction, pretapering and fusion. At a wavelength of 905 nm 80 % of the injected power in the single-mode fiber was transmitted in the few-mode fiber selectively exciting the LP(11) mode. The coupling behavior was experimentally investigated for the case of strong as well as weak fusion. Numerical simulations based on the super-mode coupling approach were used to estimate fabrication parameters and to discuss the modal evolution in arbitrarily fused couplers. The influence of changes in the coupler geometry on the super-modes and their modal weighting are analyzed by calculations of the effective refractive index and by modal decomposition.
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34
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Velazquez-Benitez AM, Alvarado JC, Lopez-Galmiche G, Antonio-Lopez JE, Hernández-Cordero J, Sanchez-Mondragon J, Sillard P, Okonkwo CM, Amezcua-Correa R. Six mode selective fiber optic spatial multiplexer. OPTICS LETTERS 2015; 40:1663-1666. [PMID: 25872042 DOI: 10.1364/ol.40.001663] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Low-loss all-fiber photonic lantern (PL) mode multiplexers (MUXs) capable of selectively exciting the first six fiber modes of a multimode fiber (LP01, LP11a, LP11b, LP21a, LP21b, and LP02) are demonstrated. Fabrication of the spatial mode multiplexers was successfully achieved employing a combination of either six step or six graded index fibers of four different core sizes. Insertion losses of 0.2-0.3 dB and mode purities above 9 dB are achieved. Moreover, it is demonstrated that the use of graded index fibers in a PL eases the length requirements of the adiabatic tapered transition and could enable scaling to large numbers.
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35
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Marom DM, Dunayevsky J, Sinefeld D, Blau M, Ryf R, Fontaine NK, Montoliu M, Randel S, Liu C, Ercan B, Esmaeelpour M, Chandrasekhar S, Gnauck AH, Leon-Saval SG, Bland-Hawthorn J, Salazar-Gil JR, Sun Y, Grüner-Nielsen L, Lingle R. Wavelength-selective switch with direct few mode fiber integration. OPTICS EXPRESS 2015; 23:5723-5737. [PMID: 25836802 DOI: 10.1364/oe.23.005723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The first realization of a wavelength-selective switch (WSS) with direct integration of few mode fibers (FMF) is fully described. The free-space optics FMF-WSS dynamically steers spectral information-bearing beams containing three spatial modes from an input port to one of nine output ports using a phase spatial light modulator. Sources of mode dependent losses (MDL) are identified, analytically analyzed and experimentally confirmed on account of different modal sensitivities to fiber coupling in imperfect imaging and at spectral channel edges due to mode clipping. These performance impacting effects can be reduced by adhering to provided design guidelines, which scale in support of higher spatial mode counts. The effect on data transmission of cascaded passband filtering and MDL build-up is experimentally investigated in detail.
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36
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García S, Gasulla I. Multi-cavity optoelectronic oscillators using multicore fibers. OPTICS EXPRESS 2015; 23:2403-2415. [PMID: 25836108 DOI: 10.1364/oe.23.002403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose the use of both homogeneous and heterogeneous multicore fibers to implement multi-cavity optoelectronic oscillators. We present design equations and examples that show the potential for unique performance in terms of spectral selectivity, tunability and high-frequency operation.
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37
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Oner BB, Üstün K, Kurt H, Okyay AK, Turhan-Sayan G. Large bandwidth mode order converter by differential waveguides. OPTICS EXPRESS 2015; 23:3186-3195. [PMID: 25836177 DOI: 10.1364/oe.23.003186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this article, we propose a large bandwidth mode-order converter design by dielectric waveguides with equal lengths but different cross-sectional areas. The efficient conversion between even and odd modes is verified by inducing required phase difference between the equal length waveguides of different widths. Y-junctions are composed of both tapered mode splitter and combiner to connect mono-mode waveguide to multi-mode waveguide. The converted mode profiles at the output port show that the device operates successfully at designed wavelengths with wide bandwidth. This study provides a novel technique to implement compact mode order converters and direction selective/sensitive photonic structures.
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38
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Lindley E, Min SS, Leon-Saval S, Cvetojevic N, Lawrence J, Ellis S, Bland-Hawthorn J. Demonstration of uniform multicore fiber Bragg gratings. OPTICS EXPRESS 2014; 22:31575-31581. [PMID: 25607107 DOI: 10.1364/oe.22.031575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fiber Bragg gratings in multicore fibers have significant potential as compact and robust filters for research and commercial applications. With the aid of an innovative, flat-fielded Mach-Zehnder interferometer, we demonstrate deep (>30 dB) narrow (100 pm at 3 dB; 90 pm at 10 dB) notches in the outer 6 cores of a 7-core fiber at a constant wavelength ( ± 15 pm). This is a crucial step in the development of FBGs operating within multimode fibers that carry an arbitrary number of spatial modes.
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39
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Ismaeel R, Lee T, Oduro B, Jung Y, Brambilla G. All-fiber fused directional coupler for highly efficient spatial mode conversion. OPTICS EXPRESS 2014; 22:11610-11619. [PMID: 24921282 DOI: 10.1364/oe.22.011610] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We model and demonstrate a simple mode selective all-fiber coupler capable of exciting specific higher order modes in two- and few-mode fibres with high efficiency and purity. The coupler is based on inter-modally phase-matching the propagation constants in each arm of the asymmetric fused coupler, formed by dissimilar fibres. At a specific coupler diameter, the launched fundamental LP(01) mode is coupled into the higher order mode (LP(11), LP(21), LP(02)) in the other arm, over a broadband wave-length range around 1550 nm. Unlike other techniques, the demonstrated coupler is composed of a multimode fiber that is weakly fused with a phase matched conventional single mode telecom fiber (SMF-28). The beating between the supermodes at the coupler waist produces a periodic power transfer between the two arms, and therefore, by monitoring the beating while tapering, it is possible to obtain optimum selection for the desired mode. High coupling efficiencies in excess of 90% for all the higher order modes were recorded over 100 nm spectral range, while insertion losses remain as low as 0.5 dB. Coupling efficiency can be further enhanced by performing slow tapering at high temperature, in order to precisely control the coupler cross-section geometry.
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40
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Jain S, Rancaño VJF, May-Smith TC, Petropoulos P, Sahu JK, Richardson DJ. Multi-element fiber technology for space-division multiplexing applications. OPTICS EXPRESS 2014; 22:3787-3796. [PMID: 24663699 DOI: 10.1364/oe.22.003787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A novel technological approach to space division multiplexing (SDM) based on the use of multiple individual fibers embedded in a common polymer coating material is presented, which is referred to as Multi-Element Fiber (MEF). The approach ensures ultralow crosstalk between spatial channels and allows for cost-effective ways of realizing multi-spatial channel amplification and signal multiplexing/demultiplexing. Both the fabrication and characterization of a passive 3-element MEF for data transmission, and an active 5-element erbium/ytterbium doped MEF for cladding-pumped optical amplification that uses one of the elements as an integrated pump delivery fiber is reported. Finally, both components were combined to emulate an optical fiber network comprising SDM transmission lines and amplifiers, and illustrate the compatibility of the approach with existing installed single-mode WDM fiber systems.
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41
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Carpenter J, Eggleton BJ, Schröder J. Reconfigurable spatially-diverse optical vector network analyzer. OPTICS EXPRESS 2014; 22:2706-2713. [PMID: 24663562 DOI: 10.1364/oe.22.002706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a spatially-diverse optical vector network analyzer which is capable of measuring the partial or complete mode transfer matrix of a system as a function of wavelength in an arbitrary mode basis using single or multiple sweeps.
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Carpenter J, Leon-Saval SG, Salazar-Gil JR, Bland-Hawthorn J, Baxter G, Stewart L, Frisken S, Roelens MAF, Eggleton BJ, Schröder J. 1x11 few-mode fiber wavelength selective switch using photonic lanterns. OPTICS EXPRESS 2014; 22:2216-2221. [PMID: 24663513 DOI: 10.1364/oe.22.002216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate an 11 port count wavelength selective switch (WSS) supporting spatial superchannels of three spatial modes, based on the combination of photonic lanterns and a high-port count single-mode WSS.
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Lu P, Shipton M, Wang A, Soker S, Xu Y. Adaptive control of waveguide modes in a two-mode-fiber. OPTICS EXPRESS 2014; 22:2955-2964. [PMID: 24663587 PMCID: PMC3927635 DOI: 10.1364/oe.22.002955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 06/03/2023]
Abstract
We experimentally demonstrate an adaptive-optics-based approach that allows selective excitation of waveguide modes and their mixtures in a two-mode fiber (TMF). A phase-only spatial light modulator is used for wavefront control, using feedback signals provided by the correlation between the experimentally measured field distribution and the desired mode profiles. Experimental results show the optical field within the TMF can be shaped to be pure linearly polarized (LP) modes or their combinations. Analysis shows selective mode excitation can be achieved using only 5 × 5 independent phase blocks. With proper feedback signals, this method should enable one to precisely control the optical field within any multimode fiber or other types of waveguides in real time.
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Affiliation(s)
- Peng Lu
- Center for Photonics Technology, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061,
USA
| | - Matthew Shipton
- Center for Photonics Technology, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061,
USA
| | - Anbo Wang
- Center for Photonics Technology, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061,
USA
| | - Shay Soker
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157,
USA
| | - Yong Xu
- Center for Photonics Technology, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061,
USA
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Leon-Saval SG, Fontaine NK, Salazar-Gil JR, Ercan B, Ryf R, Bland-Hawthorn J. Mode-selective photonic lanterns for space-division multiplexing. OPTICS EXPRESS 2014; 22:1036-44. [PMID: 24515063 DOI: 10.1364/oe.22.001036] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate a 3x1 fiber-based photonic lantern spatial-multiplexer with mode-selectivity greater than 6 dB and transmission loss of less than 0.3 dB. The total insertion loss of the mode-selective multiplexers when coupled to a graded-index few-mode fiber was < 2 dB. These mode multiplexers showed mode-dependent loss below 0.5 dB. To our knowledge these are the lowest insertion and mode-dependent loss devices, which are also fully compatible with conventional few-mode fiber technology and broadband operation.
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Spaleniak I, Jovanovic N, Gross S, Ireland MJ, Lawrence JS, Withford MJ. Integrated photonic building blocks for next-generation astronomical instrumentation II: the multimode to single mode transition. OPTICS EXPRESS 2013; 21:27197-27208. [PMID: 24216943 DOI: 10.1364/oe.21.027197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
There are numerous advantages to exploiting diffraction-limited instrumentation at astronomical observatories, which include smaller footprints, less mechanical and thermal instabilities and high levels of performance. To realize such instrumentation it is imperative to convert the atmospheric seeing-limited signal that is captured by the telescope into a diffraction-limited signal. This process can be achieved photonically by using a mode reformatting device known as a photonic lantern that performs a multimode to single-mode transition. With the aim of developing an optimized integrated photonic lantern, we undertook a systematic parameter scan of devices fabricated by the femtosecond laser direct-write technique. The devices were designed for operation around 1.55 μm. The devices showed (coupling and transition) losses of less than 5% for F/# ≥ 12 injection and the total device throughput (including substrate absorption) as high as 75-80%. Such devices show great promise for future use in astronomy.
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Betters CH, Leon-Saval SG, Robertson JG, Bland-Hawthorn J. Beating the classical limit: a diffraction-limited spectrograph for an arbitrary input beam. OPTICS EXPRESS 2013; 21:26103-26112. [PMID: 24216834 DOI: 10.1364/oe.21.026103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate a new approach to classical fiber-fed spectroscopy. Our method is to use a photonic lantern that converts an arbitrary (e.g. incoherent) input beam into N diffraction-limited outputs. For the highest throughput, the number of outputs must be matched to the total number of unpolarized spatial modes on input. This approach has many advantages: (i) after the lantern, the instrument is constructed from 'commercial off the shelf' components; (ii) the instrument is the minimum size and mass configuration at a fixed resolving power and spectral order; (iii) the throughput is better than 60% (slit to detector, including detector QE of ~80%); (iv) the scattered light at the detector can be less than 0.1% (total power). Our first implementation operates over 1545-1555 nm (limited by the detector) with a spectral resolution of 0.055 nm (R~30,000) using a 1 × 7 (1 multi-mode input to 7 single-mode outputs) photonic lantern. This approach is a first step towards a fully integrated, multimode photonic microspectrograph.
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Ozdur I, Toliver P, Agarwal A, Woodward TK. Free-space to single-mode collection efficiency enhancement using photonic lanterns. OPTICS LETTERS 2013; 38:3554-3557. [PMID: 24104812 DOI: 10.1364/ol.38.003554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate single-mode collection efficiency enhancement for free space optical systems using a photonic lantern to collect scattered infrared light from diffuse objects at far- and near-field distances. A single-mode collection efficiency improvement of ∼8 dB is demonstrated in the near-field region relative to standard single-mode fiber. The insertion loss properties of the photonic lantern are also analyzed, and an additional insertion loss penalty is observed for near-field distances when the transmitted beam is collimated. The photonic lantern can be used for coherent detection systems such as light detection and ranging and free-space optical communication with improved collection efficiency and nearly perfect mode matching.
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von Hoyningen-Huene J, Ryf R, Winzer P. LCoS-based mode shaper for few-mode fiber. OPTICS EXPRESS 2013; 21:18097-18110. [PMID: 23938681 DOI: 10.1364/oe.21.018097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Spatial light modulation can be used to address specific fiber modes, as required in mode-division multiplexed systems. We theoretically compare phase-only spatial light modulation to a combination of amplitude and phase spatial light modulation in terms of insertion loss and crosstalk for a fiber supporting 11 LP modes. We experimentally demonstrate selective mode excitation using a Liquid Crystal on Silicon (LCoS) spatial light modulator configured to as phase and amplitude modulator.
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Birks TA, Mangan BJ, Díez A, Cruz JL, Murphy DF. "Photonic lantern" spectral filters in multi-core Fiber. OPTICS EXPRESS 2012; 20:13996-14008. [PMID: 22714465 DOI: 10.1364/oe.20.013996] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Fiber Bragg gratings are written across all 120 single-mode cores of a multi-core optical Fiber. The Fiber is interfaced to multimode ports by tapering it within a depressed-index glass jacket. The result is a compact multimode "photonic lantern" filter with astrophotonic applications. The tapered structure is also an effective mode scrambler.
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Affiliation(s)
- T A Birks
- Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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Noordegraaf D, Skovgaard PMW, Sandberg RH, Maack MD, Bland-Hawthorn J, Lawrence JS, Lægsgaard J. Nineteen-port photonic lantern with multimode delivery fiber. OPTICS LETTERS 2012; 37:452-454. [PMID: 22344070 DOI: 10.1364/ol.37.000452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate efficient multimode (MM) to single-mode (SM) conversion in a 19-port photonic lantern with a 50 μm core MM delivery fiber. The photonic lantern can be used within the field of astrophotonics for coupling MM starlight to an ensemble of SM fibers in order to perform fiber-Bragg-grating-based spectral filtering. An MM delivery fiber spliced to the photonic lantern offers the advantage that the delivery fiber guides the light from the focal plane of the telescope to the splitter. Therefore, it is no longer necessary to have the splitter mounted directly in the focal plane of the telescope. The coupling loss from a 50 μm core MM fiber to an ensemble of 19 SM fibers and back to a 50 μm core MM fiber is below 1.1 dB.
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