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Chowdury A, Tan DTH. Resonant Akhmediev breathers. Sci Rep 2024; 14:10686. [PMID: 38724621 PMCID: PMC11081960 DOI: 10.1038/s41598-024-61533-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024] Open
Abstract
Modulation instability is a phenomenon in which a minor disturbance within a carrier wave gradually amplifies over time, leading to the formation of a series of compressed waves with higher amplitudes. In terms of frequency analysis, this process results in the generation of new frequencies on both sides of the original carrier wave frequency. We study the impact of fourth-order dispersion on this modulation instability in the context of nonlinear optics that lead to the formation of a series of pulses in the form of Akhmediev breather. The Akhmediev breather, a solution to the nonlinear Schrödinger equation, precisely elucidates how modulation instability produces a sequence of periodic pulses. We observe that when weak fourth-order dispersion is present, significant resonant radiation occurs, characterized by two modulation frequencies originating from different spectral bands. As an Akhmediev breather evolves, these modulation frequencies interact, resulting in a resonant amplification of spectral sidebands on either side of the breather. When fourth-order dispersion is of intermediate strength, the spectral bandwidth of the Akhmediev breather diminishes due to less pronounced resonant interactions, while stronger dispersion causes the merging of the two modulation frequency bands into a single band. Throughout these interactions, we witness a complex energy exchange process among the phase-matched frequency components. Moreover, we provide a precise explanation for the disappearance of the Akhmediev breather under weak fourth-order dispersion and its resurgence with stronger values. Our study demonstrates that Akhmediev breathers, under the influence of fourth-order dispersion, possess the capability to generate infinitely many intricate yet coherent patterns in the temporal domain.
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Affiliation(s)
- Amdad Chowdury
- Photonics Devices and Systems Group, Singapore University of Technology and Design, 8 Somapah Rd., Singapore, 487372, Singapore.
| | - Dawn T H Tan
- Photonics Devices and Systems Group, Singapore University of Technology and Design, 8 Somapah Rd., Singapore, 487372, Singapore.
- Institute of Microelectronics (IME), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-02, Singapore, 138634, Singapore.
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2
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Yang Z, Dong W, Fan Z, He S, Chen N, Li H, Zhou H, Zhang X, Xu J. 40 Gb/s multimode all-optical regenerator based on the low-loss silicon-based nanowaveguide. OPTICS EXPRESS 2024; 32:6507-6519. [PMID: 38439351 DOI: 10.1364/oe.508059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/23/2024] [Indexed: 03/06/2024]
Abstract
With the increasing demand for communication capacity, all-optical regeneration of multimode signals is a helpful technology of network nodes and optical signal processors. However, the difficulty of regenerating signal in higher-order modes hinders the practical application of multimode all-optical regenerators. In this study, we experimentally demonstrate the 40 Gb/s all-optical regeneration of NRZ-OOK signal in TE0 and TE1 modes via four-wave mixing (FWM) in the low-loss silicon-based nanowaveguide. By optimizing the parameters of waveguide section to enhance FWM conversion efficiency of two modes, and introducing Euler bending to reduce crosstalk between modes, the transmission loss of the silicon waveguide is 0.3 dB/cm, and the FWM conversion efficiency of the multimode regenerator is as high as -9.6 dB (TE0) and -13.0 dB (TE1). Both modes achieve extinction ratio enhancement of about 6 dB after regeneration. This silicon-based all-optical regenerator has great application potential in all-optical signal processing systems.
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3
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Sirleto L, Righini GC. An Introduction to Nonlinear Integrated Photonics: Structures and Devices. MICROMACHINES 2023; 14:614. [PMID: 36985020 PMCID: PMC10051308 DOI: 10.3390/mi14030614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/24/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
The combination of integrated optics technologies with nonlinear photonics, which has led to growth of nonlinear integrated photonics, has also opened the way to groundbreaking new devices and applications. In a companion paper also submitted for publication in this journal, we introduce the main physical processes involved in nonlinear photonics applications and discuss the fundaments of this research area. The applications, on the other hand, have been made possible by availability of suitable materials with high nonlinear coefficients and/or by design of guided-wave structures that can enhance a material's nonlinear properties. A summary of the traditional and innovative nonlinear materials is presented there. Here, we discuss the fabrication processes and integration platforms, referring to semiconductors, glasses, lithium niobate, and two-dimensional materials. Various waveguide structures are presented. In addition, we report several examples of nonlinear photonic integrated devices to be employed in optical communications, all-optical signal processing and computing, or in quantum optics. We aimed at offering a broad overview, even if, certainly, not exhaustive. However, we hope that the overall work will provide guidance for newcomers to this field and some hints to interested researchers for more detailed investigation of the present and future development of this hot and rapidly growing field.
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Affiliation(s)
- Luigi Sirleto
- National Research Council (CNR), Institute of Applied Sciences and Intelligent Systems (ISASI), Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Giancarlo C. Righini
- National Research Council (CNR), Institute of Applied Physics “Nello Carrara” (IFAC), Via Madonna del Piano 10, Sesto Fiorentino, 50019 Florence, Italy
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4
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A photonic integrated continuous-travelling-wave parametric amplifier. Nature 2022; 612:56-61. [DOI: 10.1038/s41586-022-05329-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/07/2022] [Indexed: 12/05/2022]
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5
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A topological nonlinear parametric amplifier. Nat Commun 2022; 13:7218. [PMID: 36433968 PMCID: PMC9700758 DOI: 10.1038/s41467-022-34979-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/14/2022] [Indexed: 11/27/2022] Open
Abstract
Topological boundary states are well localized eigenstates at the boundary between two different bulk topologies. As long as bulk topology is preserved, the topological boundary mode will endure. Here, we report topological nonlinear parametric amplification of light in a dimerized coupled waveguide system based on the Su-Schrieffer-Heeger model with a domain wall. The good linear transmission properties of the topological waveguide arising from the strong localization of light to the topological boundary is demonstrated through successful high-speed transmission of 30 Gb/s non-return-to-zero and 56 Gb/s pulse amplitude 4-level data. The strong localization of a co-propagating pump and probe to the boundary waveguide is harnessed for efficient, low power optical parametric amplification and wavelength conversion. A nonlinear tuning mechanism is shown to induce chiral symmetry breaking in the topological waveguide, demonstrating a pathway in which Kerr nonlinearities may be applied to tune the topological boundary mode and control the transition to bulk states.
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6
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Bornacelli J, Araiza-Sixtos FA, Torres-Torres C, Hernández-Acosta MA, Oliver A, Rangel-Rojo R. Driving Third-Order Optical Nonlinearities in Photoluminescent Si Nanoparticles by Nitrogen Co-Implantation in a Silica Matrix. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5670. [PMID: 36013807 PMCID: PMC9413631 DOI: 10.3390/ma15165670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/16/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
The photoluminescence and third-order nonlinear optical effects of co-implanted silicon nanoparticles and nitrogen ions in a silica matrix were studied. Experimental evidence shows the potential of nitrogen ions for changing optical properties exhibited by silicon nanoparticles implanted in an integrated system. The modification of the optical bandgap and photoluminescent intensity in the studied nanomaterials by the incorporation of nitrogen was analyzed. Standard two-wave mixing experiments were conducted using nanosecond and picosecond laser pulses at 532 nm wavelength. At this off-resonance condition, only multiphoton excitation can promote electrons at energies above the optical bandgap of the silicon nanoparticles. The picosecond results show that the co-implanted sample with nitrogen exhibits a three-fold enhancement of the nonlinear Kerr response. Femtosecond z-scan measurements were undertaken at 800 nm in order to explore the modification of the ultrafast nonlinear response of the samples that revealed a purely electronic Kerr nonlinearity together to saturable absorption of the SiNPs in the near-infrared. Remarkably, femtosecond results reveal that nitrogen co-implantation in the SiNPs system derives from the quenching of the third-order nonlinear optical behavior. These findings pointed out a simple approach for engineering the optical bandgap of nanocomposites, which can be controlled by a doping process based on ion-implanted nitrogen. It is highlighted that the enhanced light-matter interactions induced by nitrogen implantation can be useful for developing nonlinear integrated silicon photonics nanodevices with low power excitation.
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Affiliation(s)
- Jhovani Bornacelli
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Fernando Arturo Araiza-Sixtos
- Departamento de Óptica, Centro de Investigación Científica y Educación Superior de Ensenada, A.P. 360, Ensenada 22860, Mexico
| | - Carlos Torres-Torres
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Zacatenco, Instituto Politécnico Nacional, Ciudad de México 07738, Mexico
| | - Marco Antonio Hernández-Acosta
- Departamento de Óptica, Centro de Investigación Científica y Educación Superior de Ensenada, A.P. 360, Ensenada 22860, Mexico
| | - Alicia Oliver
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Raúl Rangel-Rojo
- Departamento de Óptica, Centro de Investigación Científica y Educación Superior de Ensenada, A.P. 360, Ensenada 22860, Mexico
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7
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Nanoscale optical parametric amplification through super-nonlinearity induction. APPLIED NANOSCIENCE 2022. [DOI: 10.1007/s13204-022-02527-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
AbstractOptical parametric amplification (OPA) is a nonlinear process through which a low-power input wave is amplified by extracting energy from an interaction medium that is energized by a high-intensity pump wave. For a significant amplification of an input wave, a sufficiently long interaction medium is required, which is usually on the order of a few centimeters. Therefore, in the small scale, OPA is considered unfeasible, and this prevents it from being employed in micro and nanoscale devices. There have been recent studies that proposed microscale OPA through the use of micro-resonators. However, there is currently no study that has suggested high-gain nanoscale OPA, which could be quite useful for implementing nanoscale optical devices. This study aims to show that nanoscale OPA is feasible through the concurrent maximization of the pump wave induced electric energy density and the polarization density (nonlinear coupling strength) within the interaction medium, which enables a very high amount of energy to be transferred to the input wave that is sufficient to amplify the input wave with a gain factor that is comparable to those provided by centimeter scale nonlinear crystals. The computational results of our OPA model match with the experimental ones in the context of sum-harmonic generation, which is the wave-mixing process that gives rise to OPA, with an accuracy of 97.6%. The study aims to make room for further investigation of nanoscale OPA through adaptive optics and/or nonlinear programming algorithms for the enhancement of the process.
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8
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Mobini E, Espinosa DHG, Vyas K, Dolgaleva K. AlGaAs Nonlinear Integrated Photonics. MICROMACHINES 2022; 13:mi13070991. [PMID: 35888808 PMCID: PMC9323658 DOI: 10.3390/mi13070991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 01/18/2023]
Abstract
Practical applications implementing integrated photonic circuits can benefit from nonlinear optical functionalities such as wavelength conversion, all-optical signal processing, and frequency-comb generation, among others. Numerous nonlinear waveguide platforms have been explored for these roles; the group of materials capable of combining both passive and active functionalities monolithically on the same chip is III–V semiconductors. AlGaAs is the most studied III–V nonlinear waveguide platform to date; it exhibits both second- and third-order optical nonlinearity and can be used for a wide range of integrated nonlinear photonic devices. In this review, we conduct an extensive overview of various AlGaAs nonlinear waveguide platforms and geometries, their nonlinear optical performances, as well as the measured values and wavelength dependencies of their effective nonlinear coefficients. Furthermore, we highlight the state-of-the-art achievements in the field, among which are efficient tunable wavelength converters, on-chip frequency-comb generation, and ultra-broadband on-chip supercontinuum generation. Moreover, we overview the applications in development where AlGaAs nonlinear functional devices aspire to be the game-changers. Among such applications, there is all-optical signal processing in optical communication networks and integrated quantum photonic circuits.
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Affiliation(s)
- Ehsan Mobini
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada;
| | - Daniel H. G. Espinosa
- School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (D.H.G.E.); (K.V.)
| | - Kaustubh Vyas
- School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (D.H.G.E.); (K.V.)
| | - Ksenia Dolgaleva
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada;
- School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (D.H.G.E.); (K.V.)
- Correspondence:
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9
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Supercontinuum generation in a nonlinear ultra-silicon-rich nitride waveguide. Sci Rep 2022; 12:9487. [PMID: 35676414 PMCID: PMC9177728 DOI: 10.1038/s41598-022-13734-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/09/2022] [Indexed: 12/05/2022] Open
Abstract
Supercontinuum generation is demonstrated in a 3-mm-long ultra-silicon-rich nitride (USRN) waveguide by launching 500 fs pulses centered at 1555 nm with a pulse energy of 17 pJ. The generated supercontinuum is experimentally characterized to possess a high spectral coherence, with an average |g12| exceeding 0.90 across the wavelength range of the coherence measurement (1260 nm to 1700 nm). Numerical simulations further indicate a high coherence over the full spectrum. The experimentally measured supercontinuum agrees well with the theoretical simulations based on the generalized nonlinear Schrödinger equation. The generated broadband spectra using 500 fs pulses possessing high spectral coherence provide a promising route for CMOS-compatible light sources for self-referencing applications, metrology, and imaging.
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10
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A Review of Capabilities and Scope for Hybrid Integration Offered by Silicon-Nitride-Based Photonic Integrated Circuits. SENSORS 2022; 22:s22114227. [PMID: 35684846 PMCID: PMC9185365 DOI: 10.3390/s22114227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 12/23/2022]
Abstract
In this review we present some of the recent advances in the field of silicon nitride photonic integrated circuits. The review focuses on the material deposition techniques currently available, illustrating the capabilities of each technique. The review then expands on the functionalisation of the platform to achieve nonlinear processing, optical modulation, nonvolatile optical memories and integration with III-V materials to obtain lasing or gain capabilities.
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11
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Ma C, Hou J, Yang C, Shi M, Chen S. Complete photonic bandgap in silicon nitride slab assisted by effective index difference between polarizations. FRONTIERS OF OPTOELECTRONICS 2022; 15:20. [PMID: 36637546 PMCID: PMC9756231 DOI: 10.1007/s12200-022-00023-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/07/2021] [Indexed: 06/17/2023]
Abstract
The slab effective index difference between the transverse-electric (TE) and transverse-magnetic (TM) polarizations was utilized to obtain complete photonic bandgap (CPBG) in a silicon nitride (SixNy) photonic crystal slab. For this, coincident frequency range in the TE photonic bandgap (PBG) and TM PBG, which denotes the CPBGs of the slab, must be found with the same structure. Through adjusting the effective index pair of TE and TM polarizations by changing the thickness of the SixNy core layer, and also optimizing the structure parameters within the photonic crystal plane, a large normalized CPBG of 5.62% was theoretically obtained in a slab of SixNy with a refractive index of 2.5. Moreover, based on the obtained CPBG, a microcavity which could support both TE and TM polarization was theoretically demonstrated. The cavity modes for different polarizations were both well confined, which proved the reliability of the CPBG. In addition, using the same method, the lowest refractive index of SixNy on silica slab for a CPBG could be extended to as low as 2. The results indicate that there is potential for development of various high-performance CPBG devices based on SixNy slab technology.
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Affiliation(s)
- Can Ma
- Hubei Key Laboratory of Intelligent Wireless Communications, Hubei Engineering Research Center for Intelligent Internet of Things, College of Electronic and Information Engineering, South-Central MinZu University, Wuhan, 430074, China
| | - Jin Hou
- Hubei Key Laboratory of Intelligent Wireless Communications, Hubei Engineering Research Center for Intelligent Internet of Things, College of Electronic and Information Engineering, South-Central MinZu University, Wuhan, 430074, China.
| | - Chunyong Yang
- Hubei Key Laboratory of Intelligent Wireless Communications, Hubei Engineering Research Center for Intelligent Internet of Things, College of Electronic and Information Engineering, South-Central MinZu University, Wuhan, 430074, China
| | - Ming Shi
- Hubei Key Laboratory of Intelligent Wireless Communications, Hubei Engineering Research Center for Intelligent Internet of Things, College of Electronic and Information Engineering, South-Central MinZu University, Wuhan, 430074, China
| | - Shaoping Chen
- Hubei Key Laboratory of Intelligent Wireless Communications, Hubei Engineering Research Center for Intelligent Internet of Things, College of Electronic and Information Engineering, South-Central MinZu University, Wuhan, 430074, China
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12
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Enhanced photonics devices based on low temperature plasma-deposited dichlorosilane-based ultra-silicon-rich nitride (Si 8N). Sci Rep 2022; 12:5267. [PMID: 35347190 PMCID: PMC8960789 DOI: 10.1038/s41598-022-09227-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/21/2022] [Indexed: 11/08/2022] Open
Abstract
Ultra-silicon-rich nitride with refractive indices ~ 3 possesses high nonlinear refractive index-100× higher than stoichiometric silicon nitride and presents absence of two-photon absorption, making it attractive to be used in nonlinear integrated optics at telecommunications wavelengths. Despite its excellent nonlinear properties, ultra-silicon-rich nitride photonics devices reported so far still have fairly low quality factors of [Formula: see text], which could be mainly attributed by the material absorption bonds. Here, we report low temperature plasma-deposited dichlorosilane-based ultra-silicon-rich nitride (Si8N) with lower material absorption bonds, and ~ 2.5× higher quality factors compared to ultra-silicon-rich nitride conventionally prepared with silane-based chemistry. This material is found to be highly rich in silicon with refractive indices of ~ 3.12 at telecommunications wavelengths and atomic concentration ratio Si:N of ~ 8:1. The material morphology, surface roughness and binding energies are also investigated. Optically, the material absorption bonds are quantified and show an overall reduction. Ring resonators fabricated exhibit improved intrinsic quality factors [Formula: see text], ~ 2.5× higher compared to conventional silane-based ultra-silicon-rich nitride films. This enhanced quality factor from plasma-deposited dichlorosilane-based ultra-silicon-rich nitride signifies better photonics device performance using these films. A pathway has been opened up for further improved device performance of ultra-silicon-rich nitride photonics devices at material level tailored by choice of different chemistries.
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Ayan A, Mazeas F, Liu J, Kippenberg TJ, Brès CS. Polarization selective ultra-broadband wavelength conversion in silicon nitride waveguides. OPTICS EXPRESS 2022; 30:4342-4350. [PMID: 35209672 DOI: 10.1364/oe.446357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
We experimentally demonstrate broadband degenerate continuous-wave four-wave mixing in long silicon nitride (Si3N4) waveguides for operation both in the telecommunication L-band and the thulium band near 2 µm by leveraging polarization dependence of the waveguide dispersion. Broadband conversion is typically demonstrated in short milimeter long waveguides as the bandwidth is linked to the interaction length. This makes it challenging to simultaneously push bandwidth and efficiency, imposing stringent constraints on dispersion engineering. In this work, we show conversion bandwidths larger than 150 nm in the L-band when pumping in the transverse magnetic (TM) mode and larger than 120 nm at 2 µm when using transverse electric excitation, despite the use of 0.5 m long waveguides. In addition, we also show how extreme polarization selectivity can be leveraged in a single waveguide to enable switchable distant phase-matching based on higher-order dispersion. Relying on this approach, we demonstrate the selective conversion of light from the telecom band to the O-band for TM polarization or to the mid-infrared light up to 2.5 µm in TE. Our experiments are in excellent agreement with simulations, showing the high potential of the platform for broadband and distant conversion beyond the telecom band.
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Khan AN, Younis U, Mehmood MQ, Zubair M. Atmospheric propagation of space-fractional Gaussian-beam waves in a FSO communication system. OPTICS EXPRESS 2022; 30:1570-1583. [PMID: 35209314 DOI: 10.1364/oe.446708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
We present a novel, self-consistent analytical model of Gaussian-beam propagation through the atmospheric turbulence by solving the paraxial wave equation in a fractional-dimension space of dimension D, in the range 2 < D ≤ 3, corresponding to the effective spatial dimension experienced by the beam under given turbulent conditions in a free space optical (FSO) communication system. The well-known refractive index structure parameter (C n2) has been mapped from D = 2.668 (C n2≈10-13, strong fluctuations) to D = 2.999 (C n2≈10-16, weak fluctuations) in our simple analytical model, whereas D = 3 corresponds to the ideal case of free-space propagation under zero turbulence. Finally, an optimization problem is developed to mitigate the effects of atmospheric turbulence, leading to efficient transceiver design for the FSO communication system to ensure the reliability of links under varying atmospheric turbulence.
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3D printed and spiral lithographically patterned erbium-doped polymer micro-waveguide amplifiers. Sci Rep 2021; 11:21292. [PMID: 34711919 PMCID: PMC8553943 DOI: 10.1038/s41598-021-00805-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/12/2021] [Indexed: 11/08/2022] Open
Abstract
Infrared (IR)-emitting RE doped materials have been extensively used to fabricate active components of integrated optical devices in various fields, such as fiber amplifiers, telecommunications, optoelectronics, and waveguides. Among various RE elements, trivalent erbium ions (Er 3+) are of great interest since their emissive behavior span the low loss telecommunication window of 1300–1650 nm. In this paper, we report two types of polymeric waveguide amplifiers. 8 cm long, lithographically patterned spiral waveguides provide 8 dB of gain using a 980 nm pump power of 95 mW. Gain is observed from 1530 to 1590 nm. We further report the first demonstration of polymeric waveguide amplifiers fabricated using 3D printing methods based on two-photon lithography, paving the way for rapid prototyping of active 3D printed devices and active photonic devices which may transcend planar limitations.
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16
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Yang Z, Zhang R, Wang Z, Xu P, Zhang W, Kang Z, Zheng J, Dai S, Wang R, Majumdar A. High-Q, submicron-confined chalcogenide microring resonators. OPTICS EXPRESS 2021; 29:33225-33233. [PMID: 34809138 DOI: 10.1364/oe.434808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate high quality (Q) factor microring resonators in high index-contrast GeSbSe chalcogenide glass waveguides using electron-beam lithography followed by plasma dry etching. A microring resonator with a radius of 90 μm shows an intrinsic Q factor of 4.1 × 105 in the telecom band. Thanks to the submicron waveguide dimension, the effective nonlinear coefficient was determined to be up to ∼110 W-1m-1 at 1550 nm, yielding a larger figure-of-merit compared with previously reported submicron chalcogenide waveguides. Such a high Q factor, combined with the large nonlinear coefficient and high confinement, shows the great potential of the GeSbSe microring resonator as a competitive platform in integrated nonlinear photonics.
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Nejadriahi H, Pappert S, Fainman Y, Yu P. Efficient and compact thermo-optic phase shifter in silicon-rich silicon nitride. OPTICS LETTERS 2021; 46:4646-4649. [PMID: 34525072 DOI: 10.1364/ol.431757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
The design, fabrication, and characterization of low-loss ultra-compact bends in high-index (n=3.1 at λ=1550nm) plasma-enhanced chemical vapor deposition silicon-rich silicon nitride (SRN) were demonstrated and utilized to realize efficient, small footprint thermo-optic phase shifter. Compact bends were structured into a folded waveguide geometry to form a rectangular spiral within an area of 65×65µm2, having a total active waveguide length of 1.2 mm. The device featured a phase-shifting efficiency of 8mW/π and a 3 dB switching bandwidth of 15 KHz. We propose SRN as a promising thermo-optic platform that combines the properties of silicon and stoichiometric silicon nitride.
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18
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Friedman A, Nejadriahi H, Sharma R, Fainman Y. Demonstration of the DC-Kerr effect in silicon-rich nitride. OPTICS LETTERS 2021; 46:4236-4239. [PMID: 34469983 DOI: 10.1364/ol.432359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate the DC-Kerr effect in plasma enhanced chemical vapor deposition (PECVD) silicon-rich nitride (SRN) and use it to demonstrate a third order nonlinear susceptibility, χ(3), as high as (6±0.58)×10-19m2/V2. We employ spectral shift versus applied voltage measurements in a racetrack resonator as a tool to characterize the nonlinear susceptibilities of these films. In doing so, we demonstrate a χ(3) larger than that of silicon and argue that PECVD SRN can provide a versatile platform for employing optical phase shifters while maintaining a low thermal budget using a deposition technique readily available in CMOS process flows.
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19
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Observation of Ultrashort Laser Pulse Evolution in a Silicon Photonic Crystal Waveguide. MICROMACHINES 2021; 12:mi12080911. [PMID: 34442533 PMCID: PMC8399431 DOI: 10.3390/mi12080911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/23/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022]
Abstract
Using the sum frequency generation cross-correlation frequency-resolved optical gating (SFG-XFROG) measurement setup, we observed the soliton evolution of low energy pulse in an Si photonic crystal waveguide, and it exhibited the pulse broadening, blue shift, and evident pulse acceleration. The soliton evolution was also investigated by nonlinear Schrödinger equation (NLSE) modelling simulation, and the simulated results agreed well with the experimental measurements. The effects of waveguide length on the pulse evolution were analyzed; the results showed that the pulse width changed periodically with increasing waveguide length. The results further the understanding of the ultra-fast nonlinear dynamics of solitons in silicon waveguides, and are helpful to soliton-based functional elements on CMOS-compatible platforms.
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Choi JW, Sahin E, Sohn BU, Chen GFR, Ng DKT, Agarwal AM, Kimerling LC, Tan DTH. High spectro-temporal compression on a nonlinear CMOS-chip. LIGHT: SCIENCE & APPLICATIONS 2021; 10:130. [PMID: 34140461 PMCID: PMC8211677 DOI: 10.1038/s41377-021-00572-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/24/2021] [Accepted: 06/04/2021] [Indexed: 05/25/2023]
Abstract
AbstractOptical pulses are fundamentally defined by their temporal and spectral properties. The ability to control pulse properties allows practitioners to efficiently leverage them for advanced metrology, high speed optical communications and attosecond science. Here, we report 11× temporal compression of 5.8 ps pulses to 0.55 ps using a low power of 13.3 W. The result is accompanied by a significant increase in the pulse peak power by 9.4×. These results represent the strongest temporal compression demonstrated to date on a complementary metal–oxide–semiconductor (CMOS) chip. In addition, we report the first demonstration of on-chip spectral compression, 3.0× spectral compression of 480 fs pulses, importantly while preserving the pulse energy. The strong compression achieved at low powers harnesses advanced on-chip device design, and the strong nonlinear properties of backend-CMOS compatible ultra-silicon-rich nitride, which possesses absence of two-photon absorption and 500× larger nonlinear parameter than in stoichiometric silicon nitride waveguides. The demonstrated work introduces an important new paradigm for spectro-temporal compression of optical pulses toward turn-key, on-chip integrated systems for all-optical pulse control.
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High-yield, wafer-scale fabrication of ultralow-loss, dispersion-engineered silicon nitride photonic circuits. Nat Commun 2021; 12:2236. [PMID: 33863901 PMCID: PMC8052462 DOI: 10.1038/s41467-021-21973-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 02/17/2021] [Indexed: 01/19/2023] Open
Abstract
Low-loss photonic integrated circuits and microresonators have enabled a wide range of applications, such as narrow-linewidth lasers and chip-scale frequency combs. To translate these into a widespread technology, attaining ultralow optical losses with established foundry manufacturing is critical. Recent advances in integrated Si3N4 photonics have shown that ultralow-loss, dispersion-engineered microresonators with quality factors Q > 10 × 106 can be attained at die-level throughput. Yet, current fabrication techniques do not have sufficiently high yield and performance for existing and emerging applications, such as integrated travelling-wave parametric amplifiers that require meter-long photonic circuits. Here we demonstrate a fabrication technology that meets all requirements on wafer-level yield, performance and length scale. Photonic microresonators with a mean Q factor exceeding 30 × 106, corresponding to 1.0 dB m−1 optical loss, are obtained over full 4-inch wafers, as determined from a statistical analysis of tens of thousands of optical resonances, and confirmed via cavity ringdown with 19 ns photon storage time. The process operates over large areas with high yield, enabling 1-meter-long spiral waveguides with 2.4 dB m−1 loss in dies of only 5 × 5 mm2 size. Using a response measurement self-calibrated via the Kerr nonlinearity, we reveal that the intrinsic absorption-limited Q factor of our Si3N4 microresonators can exceed 2 × 108. This absorption loss is sufficiently low such that the Kerr nonlinearity dominates the microresonator’s response even in the audio frequency band. Transferring this Si3N4 technology to commercial foundries can significantly improve the performance and capabilities of integrated photonics. For widespread technological application of nonlinear photonic integrated circuits, ultralow optical losses and high fabrication throughput are required. Here, the authors present a CMOS fabrication technique that realizes integrate photonic microresonators on waver-level with mean quality factors exceeding 30 million and 1 dB/m optical losses.
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Higher order mode supercontinuum generation in tantalum pentoxide (Ta 2O 5) channel waveguide. Sci Rep 2021; 11:7978. [PMID: 33846403 PMCID: PMC8042067 DOI: 10.1038/s41598-021-86922-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/18/2021] [Indexed: 11/08/2022] Open
Abstract
We fabricated tantalum pentoxide (Ta2O5) channel waveguides and used them to experimentally demonstrate higher-order mode supercontinuum (SC) generation. The Ta2O5 waveguide has a high nonlinear refractive index which was in an order magnitude of 10-14 cm2/W and was designed to be anomalously dispersive at the pumping wavelength. To the best of our knowledge, this is the first time a higher-order mode femtosecond pump based broadband SC has been measured from a nonlinear waveguide using the phase-matching method. This enabled us to demonstrate a SC spectrum spanning from 842 to 1462 nm (at - 30 dB), which corresponds to 0.83 octaves, when using the TM10 waveguide mode. When using the TE10 mode, the SC bandwidth is slightly reduced for the same excitation peak power. In addition, we theoretically estimated and discussed the possibility of using the broadband higher-order modes emitted from the Ta2O5 waveguide for trapping nanoparticles. Hence, we believe that demonstrated Ta2O5 waveguide are a promising broadband light source for optical applications such as frequency metrology, Raman spectroscopy, molecular spectroscopy and optical coherence tomography.
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Yang L, Lin H, Plimmer M, Feng XJ, Chu HW, Ma YJ, Luo JT, Sun HB, Zhang JT. Possible two-photon absorption in the near-infrared region observed by cavity ring-down spectroscopy. OPTICS EXPRESS 2020; 28:39128-39136. [PMID: 33379469 DOI: 10.1364/oe.409421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/05/2020] [Indexed: 06/12/2023]
Abstract
Two-photon absorption spectra are difficult to observe using direct absorption spectroscopy especially in the near-infrared region. Cavity ring-down spectroscopy is a promising absorption spectroscopy technique which has been widely applied to linear and saturated single-photon absorption spectra. In the present study, we report the observation of a possible two-photon absorption in the near-infrared using cavity ring-down spectroscopy, namely a two-photon resonance of methane. Using an optical frequency comb, the single-photon wavenumber of the double-quantum transition has been determined to be 182 207 682.645 MHz with a standard deviation of 75 kHz.
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Pruiti NG, Klitis C, Gough C, May S, Sorel M. Thermo-optic coefficient of PECVD silicon-rich silicon nitride. OPTICS LETTERS 2020; 45:6242-6245. [PMID: 33186960 DOI: 10.1364/ol.403357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/04/2020] [Indexed: 06/11/2023]
Abstract
The thermo-optic coefficient (TOC) of photonic integrated waveguides fabricated on silicon-rich silicon nitride grown by plasma-enanched chemical vapor deposition is characterized for the first time, to the best of our knowledge. The TOC is found to increase linearly with the fractional composition of silicon over a range from that of silicon nitride to a-Si. This finding is significant for improving the power efficiency of thermally tuned photonic integrated circuits.
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Zhang Y, Wu J, Yang Y, Qu Y, Jia L, Moein T, Jia B, Moss DJ. Enhanced Kerr Nonlinearity and Nonlinear Figure of Merit in Silicon Nanowires Integrated with 2D Graphene Oxide Films. ACS APPLIED MATERIALS & INTERFACES 2020; 12:33094-33103. [PMID: 32597629 DOI: 10.1021/acsami.0c07852] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Layered two-dimensional (2D) graphene oxide (GO) films are integrated with silicon-on-insulator (SOI) nanowire waveguides to experimentally demonstrate an enhanced Kerr nonlinearity, observed through self-phase modulation (SPM). The GO films are integrated with SOI nanowires using a large-area, transfer-free, layer-by-layer coating method that yields precise control of the film thickness. The film placement and coating length are controlled by opening windows in the silica cladding of the SOI nanowires. Owing to the strong mode overlap between the SOI nanowires and the highly nonlinear GO films, the Kerr nonlinearity of the hybrid waveguides is significantly enhanced. Detailed SPM measurements using picosecond optical pulses show significant spectral broadening enhancement for SOI nanowires coated with 2.2 mm long films of 1-3 layers of GO and 0.4 mm long films with 5-20 layers of GO. By fitting the experimental results with theory, the dependence of GO's Kerr nonlinearity on layer number and pulse energy is obtained, showing interesting physical insights and trends of the layered GO films from 2D monolayers to quasi bulk-like behavior. Finally, we show that by coating SOI nanowires with GO films, the effective nonlinear parameter of SOI nanowires is increased 16-fold, with the effective nonlinear figure of merit (FOM) increasing by about 20 times to FOM > 5. These results reveal the strong potential of using layered GO films to improve the Kerr nonlinear optical performance of silicon photonic devices.
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Affiliation(s)
- Yuning Zhang
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Jiayang Wu
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Yunyi Yang
- Centre for Translational Atomaterials, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Yang Qu
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Linnan Jia
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Tania Moein
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Baohua Jia
- Centre for Translational Atomaterials, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - David J Moss
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
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Zhang T, Ooi KJA, Chen W, Ang LK, Sin Ang Y. Optical Kerr effect and third harmonic generation in topological Dirac/Weyl semimetal. OPTICS EXPRESS 2019; 27:38270-38280. [PMID: 31878597 DOI: 10.1364/oe.27.038270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
We study the nonlinear optical response generated by the massless Dirac quasiparticles residing around the topologically-protected Dirac/Weyl nodal points in three-dimensional (3D) topological semimetals. Analytical expressions of third-order interband nonlinear optical conductivities are obtained based on a quantum mechanical formalism which couples 3D Dirac fermions with multiple photons. Our results reveal that the massless Dirac fermions in three dimensions retains strong optical nonlinearity in terahertz frequency regime similar to the case of the two-dimensional Dirac fermions in graphene. At room temperature, the Kerr nonlinear refractive index and the harmonic generation susceptibility are found to be n2 = 10-11 ∼ 10-8 m2W-1 and χ(3) = 10-14 ∼ 10-8 m2V-2, respectively, in the few terahertz frequency regimes, which is comparable to graphene and orders of magnitudes stronger than many nonlinear crystals. Importantly, because 3D topological Dirac/Weyl semimetals possess bulk structural advantage not found in the strictly two-dimensional graphene, greater design flexibility and improved ease-of-fabrication in terms of photonic and optoelectronic device applications can be achieved. Our finding reveals the potential of 3D topological semimetals as a viable alternative to graphene for nonlinear optics applications.
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Sierra JH, Rangel RC, Samad RE, Vieira ND, Alayo MI, Carvalho DO. Low-loss pedestal Ta 2O 5 nonlinear optical waveguides. OPTICS EXPRESS 2019; 27:37516-37521. [PMID: 31878530 DOI: 10.1364/oe.27.037516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 11/26/2019] [Indexed: 06/10/2023]
Abstract
In this work, we investigate a pedestal tantalum oxide (Ta2O5) material platform for integrated nonlinear optics (NLO). In order to achieve low propagation losses with this material, pedestal waveguides with Ta2O5 cores were designed. The nonlinear refractive index n2 of this new platform was obtained by measuring the amount of spectral broadening due to self-phase modulation (SPM) of 23 fs optical pulses at 785 nm propagating through the waveguides. In this manner, a nonlinear index of (5.8 ± 2.0) × 10-19 m2W-1 was found for this material, which is in good agreement with values reported in related works where strip waveguides were used for a similar purpose. Furthermore, due to the pedestal configuration, propagation losses as low as 1.6 dB·cm-1 for narrow waveguides and 0.1 dB·cm-1 for large waveguides were obtained. Finite element method (FEM) mode analysis was performed to calculate the mode characteristics, as well as the effective areas of the waveguides. The high nonlinear and linear refractive indices, wide bandgap and low propagation losses make this platform ideal for applications extending from the visible into the mid-IR regions of the optical spectrum. Due the large gap, Ta2O5 should have low two photon absorption at the near-IR as well.
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Yang N, Chen L, Li L, Li Y, Zhang C, Wang Y, Wong KKY, Zhang X. Time-division-multiplexed observation bandwidth for ultrafast parametric spectro-temporal analyzer. OPTICS EXPRESS 2019; 27:30441-30448. [PMID: 31684291 DOI: 10.1364/oe.27.030441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Parametric spectro-temporal analyzer (PASTA) has been demonstrated as a powerful tool for ultrafast spectrum measurement with superior frame rate and resolution. Compared with other time-stretch-based counterparts, the temporal focusing mechanism enlarges the initial condition and enables the observation of arbitrary waveform, especially the emission spectrum. However, due to the limited conversion bandwidth of the parametric mixing-based time-lens, the observation bandwidth of PASTA is constrained within the C (conventional) band, which hinders its practical applications. To overcome this constraint, both stokes and anti-stokes conversions of the parametric mixing process are leveraged, and the concept of time division multiplexing (TDM) is introduced to ensure their separability. Therefore, the TDM-based PASTA system successfully demultiplexes the C band and L (long) band spectra in two adjacent temporal frames. It is capable of reconstructing the wavelength-to-time sequence for arbitrary waveform over a record 58-nm observation bandwidth, which can be further improved by optimizing the filters and amplifiers. Meanwhile, both of these two bands achieve 20-pm resolution, 10-MHz frame rate, and -30-dBm sensitivity. Moreover, this TDM concept can also be applied to other parametric mixing-based temporal imaging systems to enlarge the working wavelength band, such as temporal magnification.
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Wang X, Guan X, Gao S, Hu H, Oxenløwe LK, Frandsen LH. Silicon/silicon-rich nitride hybrid-core waveguide for nonlinear optics. OPTICS EXPRESS 2019; 27:23775-23784. [PMID: 31510277 DOI: 10.1364/oe.27.023775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
A silicon/silicon-rich nitride hybrid-core waveguide has been proposed and experimentally demonstrated for nonlinear applications to fill the gap between the pure silicon waveguide and the pure silicon nitride waveguide with respect to the nonlinear properties. The hybrid-core waveguide presented here leverages the advantages of the silicon and the silicon-rich nitride waveguide platforms, showing a large nonlinearity γ of 72 ± 5 W-1 m-1 for energy-efficient four-wave mixing wavelength conversion. At the same time, the drawbacks of the material platforms are dramatically mitigated, exhibiting a reduced two-photon absorption coefficient βTPA of 0.023 cm/GW resulting in an increased nonlinear figure-of-merit as large as 21.6. A four-wave-mixing conversion efficiency as large as -5.3 dB has been achieved with the promise to be larger than 0 dB. These findings are strong arguments supporting the silicon/silicon-rich nitride hybrid-core waveguide to be used for energy-efficient nonlinear photonic applications.
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Chen GFR, Choi JW, Sahin E, Ng DKT, Tan DTH. On-chip 1 by 8 coarse wavelength division multiplexer and multi-wavelength source on ultra-silicon-rich nitride. OPTICS EXPRESS 2019; 27:23549-23557. [PMID: 31510630 DOI: 10.1364/oe.27.023549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
An 8-channel coarse wavelength division multiplexer (CWDM) based on coupled vertical gratings has been designed, fabricated and characterized. The devices are implemented on the ultra-silicon-rich nitride (USRN) platform. The demonstrated device possesses 8 CWDM channels. The absence of free spectral range (FSR) enabled the overall multiplexed bandwidth to span across the S + C + L bands. The CWDM channels meet the specifications stipulated by the International Telecommunications Union G.694.2 standard. The average channel crosstalk is -25dB. Pseudo-Random Bit Sequence 231-1 Non-Return-Zero data at 30Gb/s was launched into the device and a clear eye diagram was obtained. The device was further used with a USRN waveguide generating supercontinuum to create a multi-wavelength source emitting light at 8 CWDM wavelengths.
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Sohn BU, Choi JW, Ng DKT, Tan DTH. Optical nonlinearities in ultra-silicon-rich nitride characterized using z-scan measurements. Sci Rep 2019; 9:10364. [PMID: 31316096 PMCID: PMC6637241 DOI: 10.1038/s41598-019-46865-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/05/2019] [Indexed: 11/09/2022] Open
Abstract
The dispersive nonlinear refractive index of ultra-silicon-rich nitride, and its two-photon and three-photon absorption coefficients are measured in the wavelength range between 0.8 µm-1.6 µm, covering the O- to L - telecommunications bands. In the two-photon absorption range, the measured nonlinear coefficients are compared to theoretically calculated values with a simple parabolic band structure. Two-photon absorption is observed to exist only at wavelengths lower than 1.2 μm. The criterion for all-optical switching through the material is investigated and it is shown that ultra-silicon-rich nitride is a good material in the three-photon absorption region, which spans the entire O- to L- telecommunications bands.
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Affiliation(s)
- Byoung-Uk Sohn
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 487372, Singapore, Singapore
| | - Ju Won Choi
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 487372, Singapore, Singapore
| | - Doris K T Ng
- Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-02, Innovis Tower, 138634, Singapore, Singapore
| | - Dawn T H Tan
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 487372, Singapore, Singapore.
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Lamy M, Finot C, Parriaux A, Lacava C, Bucio TD, Gardes F, Millot G, Petropoulos P, Hammani K. Si-rich Si nitride waveguides for optical transmissions and toward wavelength conversion around 2 μm. APPLIED OPTICS 2019; 58:5165-5169. [PMID: 31503610 DOI: 10.1364/ao.58.005165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/03/2019] [Indexed: 06/10/2023]
Abstract
We show that subwavelength Si-rich nitride waveguides efficiently sustain high-speed transmissions at 2 μm. We report the transmission of a 10 Gbit/s signal over 3.5 cm with negligible power penalty. Parametric conversion in the pulsed pump regime is also demonstrated using the same waveguide structure with an efficiency as high as -18 dB.
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Ye Z, Fülöp A, Helgason ÓB, Andrekson PA, Torres-Company V. Low-loss high-Q silicon-rich silicon nitride microresonators for Kerr nonlinear optics. OPTICS LETTERS 2019; 44:3326-3329. [PMID: 31259952 DOI: 10.1364/ol.44.003326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Silicon nitride is a dielectric material widely used for applications in linear and nonlinear optics. It has an ultra-broad transparency window, low intrinsic loss, and a refractive index that allows for moderate optical field confinement in waveguides. The chemical composition of this material can be precisely set during the fabrication process, leading to an extra degree of freedom for tailoring the optical and mechanical properties of photonic chips. Silicon-rich silicon nitride waveguides are appealing for nonlinear optics, because they have a higher nonlinear Kerr coefficient and refractive index than what is possible with stoichiometric silicon nitride. This is a direct consequence of the increased silicon content. However, silicon-rich silicon nitride waveguides typically display higher absorption losses. In this Letter, we report low-loss (∼0.4 dB/cm) silicon-rich silicon nitride waveguides. The structures feature high optical confinement and can be engineered with low anomalous dispersion. We find an optimum silicon composition that, through an annealing process, overcomes optical losses associated to N-H bonds in the telecom band. Based on this technology, we successfully fabricate microresonators with mean quality factors (Q) ∼0.8×106 in the C and L bands. Broadband coherent microresonator frequency combs are generated in this platform, indicating its potential for efficient Kerr nonlinear optics.
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Stassen E, Pu M, Semenova E, Zavarin E, Lundin W, Yvind K. High-confinement gallium nitride-on-sapphire waveguides for integrated nonlinear photonics. OPTICS LETTERS 2019; 44:1064-1067. [PMID: 30821771 DOI: 10.1364/ol.44.001064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate a highly effective nonlinearity of 7.3 W-1 m-1 in a high-confinement gallium nitride-on-sapphire waveguide by performing four-wave mixing characterization at telecom wavelengths. Benefitting from a high-index-contrast waveguide layout, we can engineer the device dispersion efficiently and achieve broadband four-wave mixing operation over more than 100 nm. The intrinsic material nonlinearity of gallium nitride is extracted. Furthermore, we fabricate microring resonators with quality factors above 100,000, which will be promising for various nonlinear applications.
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Chiles J, Nader N, Hickstein DD, Yu SP, Briles TC, Carlson D, Jung H, Shainline JM, Diddams S, Papp SB, Nam SW, Mirin RP. Deuterated silicon nitride photonic devices for broadband optical frequency comb generation. OPTICS LETTERS 2018; 43:1527-1530. [PMID: 29601021 DOI: 10.1364/ol.43.001527] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
We report and characterize low-temperature, plasma-deposited deuterated silicon nitride films for nonlinear integrated photonics. With a peak processing temperature less than 300°C, it is back-end compatible with complementary metal-oxide semiconductor substrates. We achieve microresonators with a quality factor of up to 1.6×106 at 1552 nm and >1.2×106 throughout λ=1510-1600 nm, without annealing or stress management (film thickness of 920 nm). We then demonstrate the immediate utility of this platform in nonlinear photonics by generating a 1 THz free-spectral-range, 900 nm bandwidth modulation-instability microresonator Kerr comb and octave-spanning, supercontinuum-broadened spectra.
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Lo CW, Stefani A, de Sterke CM, Blanco-Redondo A. Analysis and design of fibers for pure-quartic solitons. OPTICS EXPRESS 2018; 26:7786-7796. [PMID: 29609328 DOI: 10.1364/oe.26.007786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
The recently discovered pure-quartic solitons, arising from the interaction of quartic dispersion and Kerr nonlinearity, open the door to unexplored soliton regimes and ultrafast laser science. Here, we report a general analysis of the dispersion and nonlinear properties necessary to observe pure-quartic solitons in optical platforms. We apply this analysis, in combination with numerical calculations, to the design of pure-quartic soliton supporting microstructured optical fibers. The designs presented here, which have realistic fabrication tolerances, support unperturbed pure-quartic soliton propagation providing access to an unmatched platform to study novel soliton physics.
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Guan X, Hu H, Oxenløwe LK, Frandsen LH. Compact titanium dioxide waveguides with high nonlinearity at telecommunication wavelengths. OPTICS EXPRESS 2018; 26:1055-1063. [PMID: 29401978 DOI: 10.1364/oe.26.001055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/05/2018] [Indexed: 06/07/2023]
Abstract
Dense integration of photonic integrated circuits demands waveguides simultaneously fulfilling requirements on compactness, low loss, high nonlinearity, and capabilities for mass production. In this work, titanium dioxide waveguides with a thick core of 380 nm exhibiting a compact mode size (0.43 μm2) and a low loss (5.4 ± 1 dB/cm) at telecommunication wavelengths around 1550 nm have been fabricated and measured. A microring resonator having a 50 μm radius has been measured to have a loaded quality factor of 53500. Four-wave mixing experiments reveal a nonlinear parameter for the waveguides of 21-34 W-1 m-1 corresponding to a nonlinear index around 2.3-3.6 x 10-18 m2/W, which results in a wavelength conversion efficiency of -36.2 dB. These performances, together with the potentially simple dispersion engineering to the fabricated waveguides by the post processes, yield a strong promise for the titanium dioxide waveguides applied in photonic integrated circuits, especially for nonlinear implementations.
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Fan M, Yang H, Zheng P, Hu G, Yun B, Cui Y. Multilayer graphene electro-absorption optical modulator based on double-stripe silicon nitride waveguide. OPTICS EXPRESS 2017; 25:21619-21629. [PMID: 29041458 DOI: 10.1364/oe.25.021619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
A graphene electro-absorption optical modulator based on double-stripe silicon nitride waveguide is proposed and analyzed. By embedding four graphene layers in the double-stripe silicon nitride waveguide and the graphene layers co-electrode design, the total metal-graphene contact resistance can be reduced 50% and as high as 30.6GHz modulation bandwidth can be achieved theoretically. The calculated extinction ratio and figure of merit are 0.1658dB/um and 9.7, respectively. And the required switching voltage from its minimum to maximum absorption state is 3.8180V and 780.50fJ/bit power consuming can be achieved. The proposed modulator can remedy the lack of high speed modulator on the passive silicon nitride waveguide.
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Krückel CJ, Fülöp A, Ye Z, Andrekson PA, Torres-Company V. Optical bandgap engineering in nonlinear silicon nitride waveguides. OPTICS EXPRESS 2017; 25:15370-15380. [PMID: 28788964 DOI: 10.1364/oe.25.015370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
Silicon nitride is a well-established material for photonic devices and integrated circuits. It displays a broad transparency window spanning from the visible to the mid-IR and waveguides can be manufactured with low losses. An absence of nonlinear multi-photon absorption in the erbium lightwave communications band has enabled various nonlinear optic applications in the past decade. Silicon nitride is a dielectric material whose optical and mechanical properties strongly depend on the deposition conditions. In particular, the optical bandgap can be modified with the gas flow ratio during low-pressure chemical vapor deposition (LPCVD). Here we show that this parameter can be controlled in a highly reproducible manner, providing an approach to synthesize the nonlinear Kerr coefficient of the material. This holistic empirical study provides relevant guidelines to optimize the properties of LPCVD silicon nitride waveguides for nonlinear optics applications that rely on the Kerr effect.
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