1
|
Li R, Chen M, Shi X, Han W, Wang X, Zhao W, Liu J, Teng C, Deng S, Cheng Y, Yuan L. Semi-embedded slot waveguide electro-optic modulator. APPLIED OPTICS 2023; 62:7346-7353. [PMID: 37855501 DOI: 10.1364/ao.498890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/29/2023] [Indexed: 10/20/2023]
Abstract
Electro-optic modulators are essential devices on silicon photonic chips in modern optical communication networks. This paper presents a compact, low-loss electro-optic modulator. The modulation efficiency is greatly improved by embedding the lower half of the slot waveguide into the buried oxide layer and inserting graphene at the junction. The interaction of graphene with an optical field in a waveguide is studied using the finite element method. The functions of phase modulation and absorption modulation are realized by changing the gate voltage to change the chemical potential of graphene. The semi-embedded slot waveguide optical modulator has a length of 50 µm. After simulation verification, it can be used as an electro-absorption modulator and can achieve a modulation depth of 26.38 dB and an insertion loss of 0.60 dB. When used as an electro-refractive modulator, it can be realized with a linear change of phase from zero to π; the total insertion loss is only 0.59 dB. The modulator has a modulation bandwidth of 79.6 GHz, and the energy consumption as electro-absorption and electro-refraction modulation are 0.51 and 1.92 pj/bit, respectively. Compared with common electro-optic modulators, the electro-optic modulator designed in this paper has a higher modulation effect and also takes into account the advantages of low insertion loss and low energy consumption. This research is helpful for the design of higher-performance optical communication network devices.
Collapse
|
2
|
Kim M, Kim SH, Kang C, Kim S, Kee CS. Highly efficient graphene terahertz modulator with tunable electromagnetically induced transparency-like transmission. Sci Rep 2023; 13:6680. [PMID: 37095302 PMCID: PMC10126146 DOI: 10.1038/s41598-023-34020-2] [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: 02/16/2023] [Accepted: 04/22/2023] [Indexed: 04/26/2023] Open
Abstract
Graphene-based optical modulators have been extensively studied owing to the high mobility and tunable permittivity of graphene. However, weak graphene-light interactions make it difficult to achieve a high modulation depth with low energy consumption. Here, we propose a high-performance graphene-based optical modulator consisting of a photonic crystal structure and a waveguide with graphene that exhibits an electromagnetically-induced-transparency-like (EIT-like) transmission spectrum at terahertz frequency. The high quality-factor guiding mode to generate the EIT-like transmission enhances light-graphene interaction, and the designed modulator achieves a high modulation depth of 98% with a significantly small Fermi level shift of 0.05 eV. The proposed scheme can be utilized in active optical devices that require low power consumption.
Collapse
Affiliation(s)
- Myunghwan Kim
- Division of Applied Photonics System Research, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
- Optical Packaging Research Section, Electronics and Telecommunications Research Institute (ETRI), Gwangju, 61012, South Korea
| | - Seong-Han Kim
- Division of Applied Photonics System Research, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Chul Kang
- Division of Applied Photonics System Research, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Soeun Kim
- Division of Applied Photonics System Research, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
| | - Chul-Sik Kee
- Division of Applied Photonics System Research, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
| |
Collapse
|
3
|
Abstract
With the increasing demand for capacity in communications networks, the use of integrated photonics to transmit, process and manipulate digital and analog signals has been extensively explored. Silicon photonics, exploiting the complementary-metal-oxide-semiconductor (CMOS)-compatible fabrication technology to realize low-cost, robust, compact, and power-efficient integrated photonic circuits, is regarded as one of the most promising candidates for next-generation chip-scale information and communication technology (ICT). However, the electro-optic modulators, a key component of Silicon photonics, face challenges in addressing the complex requirements and limitations of various applications under state-of-the-art technologies. In recent years, the graphene EO modulators, promising small footprints, high temperature stability, cost-effective, scalable integration and a high speed, have attracted enormous interest regarding their hybrid integration with SiPh on silicon-on-insulator (SOI) chips. In this paper, we summarize the developments in the study of silicon-based graphene EO modulators, which covers the basic principle of a graphene EO modulator, the performance of graphene electro-absorption (EA) and electro-refractive (ER) modulators, as well as the recent advances in optical communications and microwave photonics (MWP). Finally, we discuss the emerging challenges and potential applications for the future practical use of silicon-based graphene EO modulators.
Collapse
|
4
|
Tu PY, Huang CC. Analysis of hybrid plasmon-phonon-polariton modes in hBN/graphene/hBN stacks for mid-infrared waveguiding. OPTICS EXPRESS 2022; 30:2863-2876. [PMID: 35209418 DOI: 10.1364/oe.449287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Guiding mid-infrared (mid-IR) signals provide wide-ranging applications including chemical sensing, thermal imaging, and optical waveguiding. To manipulate mid-IR signals on photonic chips, it is critical to build a waveguide that provides both sub-diffraction field confinement and low loss. We present a mid-IR waveguide made up of a multilayer graphene/hexagonal boron nitride (hBN) stacking (MLGhS) and a high-refractive index nanowire. The guided mode of the proposed waveguide structure is formed by coupling the fundamental volume plasmon polariton with the fundamental hyperbolic phonon polariton in hBN, and is then modulated by a high-index nanowire. Interestingly, we found that the effective index, propagation length, and mode area of the guided mode vary as the dependences of N-1, N, and N3/2, where N is the number of graphene layers. In addition, an anomalous result, which reveals Lp and Am monotonously decrease as Fermi energy increases that is not observed in conventional graphene plasmon waveguides, occurs in the present structure. The modal properties are analyzed by altering geometry effects and material parameters, and by crossing the upper Reststrahlen band of hBN from the wavevector k = 1,300 to 1,500 cm-1. Furthermore, crosstalk between adjacent waveguides are investigated to assess the degree of integration. The proposed idea not only provides a potential approach for designing tunable and large-area photonic integrated circuits, but it also has the potential to be extended to other 2D materials such as silicone, germanene, and stanene.
Collapse
|
5
|
Huang CC, Chang RJ, Cheng CW. Ultra-Low-Loss Mid-Infrared Plasmonic Waveguides Based on Multilayer Graphene Metamaterials. NANOMATERIALS 2021; 11:nano11112981. [PMID: 34835745 PMCID: PMC8626059 DOI: 10.3390/nano11112981] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/20/2022]
Abstract
Manipulating optical signals in the mid-infrared (mid-IR) range is a highly desired task for applications in chemical sensing, thermal imaging, and subwavelength optical waveguiding. To guide highly confined mid-IR light in photonic chips, graphene-based plasmonics capable of breaking the optical diffraction limit offer a promising solution. However, the propagation lengths of these materials are, to date, limited to approximately 10 µm at the working frequency f = 20 THz. In this study, we proposed a waveguide structure consisting of multilayer graphene metamaterials (MLGMTs). The MLGMTs support the fundamental volume plasmon polariton mode by coupling plasmon polaritons at individual graphene sheets over a silicon nano-rib structure. Benefiting from the high conductivity of the MLGMTs, the guided mode shows ultralow loss compared with that of conventional graphene-based plasmonic waveguides at comparable mode sizes. The proposed design demonstrated propagation lengths of approximately 20 µm (four times the current limitations) at an extremely tight mode area of 10−6A0, where A0 is the diffraction-limited mode area. The dependence of modal characteristics on geometry and material parameters are investigated in detail to identify optimal device performance. Moreover, fabrication imperfections are also addressed to evaluate the robustness of the proposed structure. Moreover, the crosstalk between two adjacent present waveguides is also investigated to demonstrate the high mode confinement to realize high-density on-chip devices. The present design offers a potential waveguiding approach for building tunable and large-area photonic integrated circuits.
Collapse
Affiliation(s)
- Chia-Chien Huang
- Institute of Nanoscience, National Chung Hsing University, Taichung 40227, Taiwan
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan; (R.-J.C.); (C.-W.C.)
- Correspondence:
| | - Ruei-Jan Chang
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan; (R.-J.C.); (C.-W.C.)
| | - Ching-Wen Cheng
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan; (R.-J.C.); (C.-W.C.)
| |
Collapse
|
6
|
Cheng Z, Cao R, Wei K, Yao Y, Liu X, Kang J, Dong J, Shi Z, Zhang H, Zhang X. 2D Materials Enabled Next-Generation Integrated Optoelectronics: from Fabrication to Applications. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2003834. [PMID: 34105275 PMCID: PMC8188205 DOI: 10.1002/advs.202003834] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/04/2021] [Indexed: 05/06/2023]
Abstract
2D materials, such as graphene, black phosphorous and transition metal dichalcogenides, have gained persistent attention in the past few years thanks to their unique properties for optoelectronics. More importantly, introducing 2D materials into silicon photonic devices will greatly promote the performance of optoelectronic devices, including improvement of response speed, reduction of energy consumption, and simplification of fabrication process. Moreover, 2D materials meet the requirements of complementary metal-oxide-semiconductor compatible silicon photonic manufacturing. A comprehensive overview and evaluation of state-of-the-art 2D photonic integrated devices for telecommunication applications is provided, including light sources, optical modulators, and photodetectors. Optimized by unique structures such as photonic crystal waveguide, slot waveguide, and microring resonator, these 2D material-based photonic devices can be further improved in light-matter interactions, providing a powerful design for silicon photonic integrated circuits.
Collapse
Affiliation(s)
- Zhao Cheng
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Rui Cao
- Institute of Microscale OptoelectronicsCollaborative Innovation Centre for Optoelectronic Science & TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro‐Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy (SZ)Shenzhen UniversityShenzhen518060P. R. China
| | - Kangkang Wei
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Yuhan Yao
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Xinyu Liu
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Jianlong Kang
- Institute of Microscale OptoelectronicsCollaborative Innovation Centre for Optoelectronic Science & TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro‐Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy (SZ)Shenzhen UniversityShenzhen518060P. R. China
| | - Jianji Dong
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Zhe Shi
- Institute of Microscale OptoelectronicsCollaborative Innovation Centre for Optoelectronic Science & TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro‐Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy (SZ)Shenzhen UniversityShenzhen518060P. R. China
| | - Han Zhang
- Institute of Microscale OptoelectronicsCollaborative Innovation Centre for Optoelectronic Science & TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro‐Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy (SZ)Shenzhen UniversityShenzhen518060P. R. China
| | - Xinliang Zhang
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074P. R. China
| |
Collapse
|
7
|
A Broadband Polarization-Insensitive Graphene Modulator Based on Dual Built-in Orthogonal Slots Plasmonic Waveguide. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11041897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A broadband polarization-insensitive graphene modulator has been proposed. The dual built-in orthogonal slots waveguide allows polarization independence for the transverse electric (TE) mode and the transverse magnetic (TM) mode. Due to the introduction of metal slots in both the vertical and horizontal directions, the optical field as well as the electro-absorption of graphene are enhanced by the plasmonic effect. The proposed electro-optic modulator shows a modulation depth of 0.474 and 0.462 dB/μm for two supported modes, respectively. An ultra-low effective index difference of 0.001 can be achieved within the wavelength range from 1100 to 1900 nm. The 3 dB-bandwidth is estimated to be 101 GHz. The power consumption is 271 fJ/bit at a modulation length of 20 μm. The proposed modulator provides high speed broadband solutions in microwave photonic systems.
Collapse
|
8
|
Cynthia S, Ahmed R, Islam S, Ali K, Hossain M. Graphene based hyperbolic metamaterial for tunable mid-infrared biosensing. RSC Adv 2021; 11:7938-7945. [PMID: 35423319 PMCID: PMC8695080 DOI: 10.1039/d0ra09781k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/12/2021] [Indexed: 12/16/2022] Open
Abstract
Plasmonic biosensors, operating in the mid-infrared (mid-IR) region, are well-suited for highly specific and label-free optical biosensing. The principle of operation is based on detecting the shift in resonance wavelength caused by the interaction of biomolecules with the surrounding medium. However, metallic plasmonic biosensors suffer from poor signal transduction and high optical losses in the mid-IR range, leading to low sensitivity. Here, we introduce a hyperbolic metamaterial (HMM) biosensor, that exploits the strong, tunable, mid-IR localization of graphene plasmons, for detecting nanometric biomolecules with high sensitivity. The HMM stack consists of alternating graphene/Al2O3 multilayers, on top of a gold grating structure with rounded corners, to produce plasmonic hotspots and enhance sensing performance. Sensitivity and figure-of-merit (FOM) can be systematically tuned, by varying the structural parameters of the HMM stack and the doping levels (Fermi energy) in graphene. Finite-difference time-domain (FDTD) analysis demonstrates that the proposed biosensor can achieve sensitivities as high as 4052 nm RIU-1 (refractive index unit) with a FOM of 11.44 RIU-1. We anticipate that the reported graphene/Al2O3 HMM device will find potential application as a mid-IR, highly sensitive plasmonic biosensor, for tunable and label-free detection.
Collapse
Affiliation(s)
- Sarah Cynthia
- Department of Electrical and Electronic Engineering, University of Dhaka Dhaka-1000 Bangladesh
| | - Rajib Ahmed
- School of Medicine, Stanford University Palo Alto California 94304 USA
| | - Sharnali Islam
- Department of Electrical and Electronic Engineering, University of Dhaka Dhaka-1000 Bangladesh
| | - Khaleda Ali
- Department of Electrical and Electronic Engineering, University of Dhaka Dhaka-1000 Bangladesh
| | - Mainul Hossain
- Department of Electrical and Electronic Engineering, University of Dhaka Dhaka-1000 Bangladesh
| |
Collapse
|
9
|
Teng D, Wang K. Theoretical Analysis of Terahertz Dielectric-Loaded Graphene Waveguide. NANOMATERIALS 2021; 11:nano11010210. [PMID: 33467556 PMCID: PMC7830585 DOI: 10.3390/nano11010210] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 11/16/2022]
Abstract
The waveguiding of terahertz surface plasmons by a GaAs strip-loaded graphene waveguide is investigated based on the effective-index method and the finite element method. Modal properties of the effective mode index, modal loss, and cut-off characteristics of higher order modes are investigated. By modulating the Fermi level, the modal properties of the fundamental mode could be adjusted. The accuracy of the effective-index method is verified by a comparison between the analytical results and numerical simulations. Besides the modal properties, the crosstalk between the adjacent waveguides, which determines the device integration density, is studied. The findings show that the effective-index method is highly valid for analyzing dielectric-loaded graphene plasmon waveguides in the terahertz region and may have potential applications in subwavelength tunable integrated photonic devices.
Collapse
Affiliation(s)
- Da Teng
- College of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou 450044, China
- Correspondence: ; Tel.: +86-0371-6550-2273
| | - Kai Wang
- Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China;
| |
Collapse
|
10
|
Aray A, Ghavami Sabouri S. Plasmonic Bragg microcavity as an efficient electro-optic modulator. OPTICS EXPRESS 2020; 28:20523-20531. [PMID: 32680109 DOI: 10.1364/oe.396700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
Plasmonic electro-optic modulators might play a pivotal role in the development of compact efficient communication devices. Here, we introduce a novel electro-optic modulator based on a plasmonic Bragg microcavity and a pockels active material. We investigate detailed design and optimization protocols of the proposed structure. With 2D scanning of geometrical parameters, an extinction ratio of 19.8 dB, insertion loss of 2.8 dB and modulation depth of 0.99 with a driving voltage of ±5 V are obtained.
Collapse
|
11
|
Yao Y, Cheng Z, Dong J, Zhang X. Performance of integrated optical switches based on 2D materials and beyond. FRONTIERS OF OPTOELECTRONICS 2020; 13:129-138. [PMID: 36641553 PMCID: PMC9743869 DOI: 10.1007/s12200-020-1058-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 05/22/2023]
Abstract
Applications of optical switches, such as signal routing and data-intensive computing, are critical in optical interconnects and optical computing. Integrated optical switches enabled by two-dimensional (2D) materials and beyond, such as graphene and black phosphorus, have demonstrated many advantages in terms of speed and energy consumption compared to their conventional silicon-based counterparts. Here we review the state-of-the-art of optical switches enabled by 2D materials and beyond and organize them into several tables. The performance tables and future projections show the frontiers of optical switches fabricated from 2D materials and beyond, providing researchers with an overview of this field and enabling them to identify existing challenges and predict promising research directions.
Collapse
Affiliation(s)
- Yuhan Yao
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhao Cheng
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jianji Dong
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Xinliang Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| |
Collapse
|
12
|
Thomaschewski M, Zenin VA, Wolff C, Bozhevolnyi SI. Plasmonic monolithic lithium niobate directional coupler switches. Nat Commun 2020; 11:748. [PMID: 32029717 PMCID: PMC7005156 DOI: 10.1038/s41467-020-14539-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/13/2020] [Indexed: 11/21/2022] Open
Abstract
Lithium niobate (LN) has been the material of choice for electro-optic modulators owing to its excellent physical properties. While conventional LN electro-optic modulators continue to be the workhorse of the modern optoelectronics, they are becoming progressively too bulky, expensive, and power-hungry to fully serve the needs of this industry. Here, we demonstrate plasmonic electro-optic directional coupler switches consisting of two closely spaced nm-thin gold nanostripes on LN substrates that guide both coupled electromagnetic modes and electrical signals that control their coupling, thereby enabling ultra-compact switching and modulation functionalities. Extreme confinement and good spatial overlap of both slow-plasmon modes and electrostatic fields created by the nanostripes allow us to achieve a 90% modulation depth with 20-μm-long switches characterized by a broadband electro-optic modulation efficiency of 0.3 V cm. Our monolithic LN plasmonic platform enables a wide range of cost-effective optical communication applications that demand μm-scale footprints, ultrafast operation and high environmental stability. Lithium niobate is essential for electro-optic modulation, however, combining it with the attractive features of plasmonics is largely unexplored. Here, the authors demonstrate ultra-compact electrooptic switching with low voltage-length product, fast nonlinear response and low capacitance.
Collapse
Affiliation(s)
- Martin Thomaschewski
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
| | - Vladimir A Zenin
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Christian Wolff
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Sergey I Bozhevolnyi
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
| |
Collapse
|
13
|
Graphene-Coated Nanowire Waveguides and Their Applications. NANOMATERIALS 2020; 10:nano10020229. [PMID: 32013043 PMCID: PMC7075138 DOI: 10.3390/nano10020229] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/25/2020] [Accepted: 01/26/2020] [Indexed: 01/27/2023]
Abstract
In recent years, graphene-coated nanowires (GCNWs) have attracted considerable research interest due to the unprecedented optical properties of graphene in terahertz (THz) and mid-infrared bands. Graphene plasmons in GCNWs have become an attractive platform for nanoscale applications in subwavelength waveguides, polarizers, modulators, nonlinear devices, etc. Here, we provide a comprehensive overview of the surface conductivity of graphene, GCNW-based plasmon waveguides, and applications of GCNWs in optical devices, nonlinear optics, and other intriguing fields. In terms of nonlinear optical properties, the focus is on saturable absorption. We also discuss some limitations of the GCNWs. It is believed that the research of GCNWs in the field of nanophotonics will continue to deepen, thus laying a solid foundation for its practical application.
Collapse
|
14
|
Alhalaili B, Vidu R, Islam MS. The Growth of Ga 2O 3 Nanowires on Silicon for Ultraviolet Photodetector. SENSORS 2019; 19:s19235301. [PMID: 31810177 PMCID: PMC6929045 DOI: 10.3390/s19235301] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 02/05/2023]
Abstract
We investigated the effect of silver catalysts to enhance the growth of Ga2O3 nanowires. The growth of Ga2O3 nanowires on a P+-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga2O3 nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga2O3 nanowires can be grown directly on the surface of silicon. The Ga2O3 nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.
Collapse
Affiliation(s)
- Badriyah Alhalaili
- Nanotechnology and Advanced Materials Program, Kuwait Institute for Scientific Research, Safat 13109, Kuwait;
- Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616, USA;
| | - Ruxandra Vidu
- Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616, USA;
- The Faculty of Materials Science and Engineering, University of Politehnica of Bucharest, 060042 Bucharest, Romania
- Correspondence:
| | - M. Saif Islam
- Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616, USA;
| |
Collapse
|
15
|
Wang B, Blaize S, Salas-Montiel R. Nanoscale plasmonic TM-pass polarizer integrated on silicon photonics. NANOSCALE 2019; 11:20685-20692. [PMID: 31642454 DOI: 10.1039/c9nr06948h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Transverse electric (TE)-pass polarizers integrated in silicon-on-insulator photonic circuits, based on hybrid plasmonic absorption, have been widely discussed as a key component for applications in information and communication technologies. Nevertheless, the complementary transverse magnetic (TM)-pass polarizer has not been developed due to the TM nature of plasmonic modes. Here, we experimentally demonstrate a nano-scale TM-pass polarizer based on TE-polarized plasmonic absorption using a periodic metal nanoparticle chain integrated on a silicon waveguide. Currently, the measured extinction ratio is 23 dB μm-1 and the insertion loss is 2.4 dB μm-1 at the central wavelength of 1.59 μm, in a device with a footprint of 630 nm (0.4λ). This polarization-selective absorption is analyzed using dispersion curves and transmission near-field scanning optical microscopy. The nanophotonic device completes an integrated polarizer based on plasmonic absorption and provides the necessary footprint for high density integration in photonic integrated circuits.
Collapse
Affiliation(s)
- Binbin Wang
- Department of Physics, Mechanics, Materials, and Nanotechnologies, L2n/ICD CNRS, Université de technologie de Troyes, Troyes 10004, France.
| | - Sylvain Blaize
- Department of Physics, Mechanics, Materials, and Nanotechnologies, L2n/ICD CNRS, Université de technologie de Troyes, Troyes 10004, France.
| | - Rafael Salas-Montiel
- Department of Physics, Mechanics, Materials, and Nanotechnologies, L2n/ICD CNRS, Université de technologie de Troyes, Troyes 10004, France.
| |
Collapse
|
16
|
Zhernovnykova OA, Popova OV, Deynychenko GV, Deynichenko TI, Bludov YV. Surface plasmon-polaritons in graphene, embedded into medium with gain and losses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:465301. [PMID: 31374561 DOI: 10.1088/1361-648x/ab3821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The paper deals with the theoretical consideration of surface plasmon-polaritons in the graphene monolayer, embedded into dielectric with spatially separated gain and losses. It is demonstrated, that presence of gain and losses in the system leads to the formation of additional mode of graphene surface plasmon-polaritons, which does not have its counterpart in the conservative system. When the gain and losses are mutually balanced, the position of exceptional point-transition point between unbroken and broken [Formula: see text]-symmetry-can be effectively tuned by graphene's doping. In the case of unbalanced gain and losses the spectrum of surface plasmon-polaritons contains spectral singularity, whose frequency is also adjustable through the electrostatic gating of graphene.
Collapse
Affiliation(s)
- O A Zhernovnykova
- Department of Mathematics, H.S. Skovoroda Kharkiv National Pedagogical University, Alchevskyh Str., 29, Kharkiv, 61002, Ukraine
| | | | | | | | | |
Collapse
|
17
|
High-Performance Transmission of Surface Plasmons in Graphene-Covered Nanowire Pairs with Substrate. NANOMATERIALS 2019; 9:nano9111594. [PMID: 31717659 PMCID: PMC6915492 DOI: 10.3390/nano9111594] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/02/2019] [Accepted: 11/07/2019] [Indexed: 01/29/2023]
Abstract
Graphene was recently proposed as a promising alternative to support surface plasmons with superior performances in the mid-infrared range. Here, we theoretically show that high-performance and low-loss transmission of graphene plasmons can be achieved by adding a silica substrate to the graphene-covered nanowire pairs. The effect of the substrate layer on mode properties has been intensively investigated by using the finite element method. Furthermore, the results show that inserting a low index material layer between the nanowire and substrate could compensate for the loss accompanied by the substrate, thus the mode properties could be adjusted to fulfill better performance. A reasonable propagation length of 15 μm and an ultra-small normalized mode area about ~10−4 could be obtained at 30 THz. The introduction of the substrate layer is crucial for practical fabrication, which provides additional freedom to tune the mode properties. The graphene-covered nanowire pairs with an extra substrate may inspire potential applications in tunable integrated nanophotonic devices.
Collapse
|
18
|
Wang B, Blaize S, Kim S, Yang H, Salas-Montiel R. In-plane electric field confinement engineering in graphene-based hybrid plasmonic waveguides. APPLIED OPTICS 2019; 58:7503-7509. [PMID: 31674401 DOI: 10.1364/ao.58.007503] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Surface plasmon polaritons (SPPs) are surface modes confined to metal-dielectric interfaces. This confinement enhances the electromagnetic field and therefore, SPPs are sensitive to surface conditions. The properties of two dimensional materials such as graphene thus can be enhanced and used to engineer nanoscale components for optical communications. However, SPPs are transverse magnetic modes with electric fields out-of-plane that limit flexibility. In this contribution, we numerically analyze the confinement and in-plane enhancement in graphene-based hybrid plasmonic waveguides. We find that plasmonic modes supported by metal nanoparticle chain waveguides provide higher in-plane enhancement compared to those supported by nano-strip and slot hybrid plasmonic waveguides. Our results contribute to the performance improvement of graphene light absorption devices, including electro-optic modulators and photodetectors.
Collapse
|
19
|
Lu H, Xiong H, Huang Z, Li Y, Dong H, He D, Dong J, Guan H, Qiu W, Zhang X, Zhu W, Yu J, Luo Y, Zhang J, Chen Z. Electron-plasmon interaction on lithium niobate with gold nanolayer and its field distribution dependent modulation. OPTICS EXPRESS 2019; 27:19852-19863. [PMID: 31503741 DOI: 10.1364/oe.27.019852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
Surface plasmon resonance (SPR) enables strong field confinement, opening thereby new avenues for device miniaturization and reducing energy consumption. Plasmonic devices with electrical tunability attract tremendous interest for various applications. Most of the current researches achieved SPR modulation with relatively large driving voltages, or by other relatively low-speed tuning approaches, such as thermo-optic, magneto-optic, acousto-optic etc. In this paper, we propose and demonstrate an efficiently electrical SPR modulation based on lithium niobate (LN) with gold nanolayer (~81 nm) via electron-plasmon interaction. Efficient intensity modulation and wavelength shift (in visible band) of ~5.7 dB/V and ~36.3 nm/V are respectively obtained with low DC current. More importantly, modulation phenomenon of field distribution dependent is also observed and experimentally unveiled. Further performance is analyzed in terms of AC modulation and polarization characteristics. This key achievement opens up opportunities for applications such as optical interconnection, electric field sensing, electrically plasmonic modulation, etc.
Collapse
|
20
|
Graphene-Coated Elliptical Nanowires for Low Loss Subwavelength Terahertz Transmission. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9112351] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Graphene has been recently proposed as a promising alternative to support surface plasmons with its superior performances in terahertz and mid-infrared range. Here, we propose a graphene-coated elliptical nanowire (GCENW) structure for subwavelength terahertz waveguiding. The mode properties and their dependence on frequency, nanowire size, permittivity and chemical potential of graphene are studied in detail by using a finite element method, they are also compared with the graphene-coated circular nanowires (GCCNWs). Results showed that the ratio of the long and short axes (b/a) of the elliptical nanowire had significant influence on mode properties, they also showed that a propagation length over 200 μm and a normalized mode area of approximately 10−4~10−3 could be obtained. Increasing b/a could simultaneously achieve both long propagation length and very small full width at half maximum (FWHM) of the focal spots. When b/a = 10, a pair of focal spots about 40 nm could be obtained. Results also showed that the GCENW had a better waveguiding performance when compared with the corresponding GCCNWs. The manipulation of Terahertz (THz) waves at a subwavelength scale using graphene plasmon (GP) may lead to applications in tunable THz components, imaging, and nanophotonics.
Collapse
|
21
|
Teng D, Wang K, Li Z, Zhao Y. Graphene-coated nanowire dimers for deep subwavelength waveguiding in mid-infrared range. OPTICS EXPRESS 2019; 27:12458-12469. [PMID: 31052785 DOI: 10.1364/oe.27.012458] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
In this paper, we show that the graphene-coated nanowire dimers could enable outstanding waveguiding performance in the mid-infrared range. The propagating properties of the fundamental graphene plasmon mode and their dependence on the nanowire radius, gap distance, nanowire permittivity and chemical potential of graphene are revealed in detail and compared with the graphene-coated circular nanowire. By improving the geometric parameters and the surface conductivity of graphene, the propagation length could reach about 9 μm, which is larger than that of the graphene-coated circular nanowire plasmon mode. Meanwhile, the effective mode area is only 10-4A0, which is one order of magnitude smaller than that of the graphene-coated circular nanowire plasmon mode. Theoretically, the propagation length could be further enhanced by increasing the chemical potential. Besides, the proposed graphene-coated nanowire dimers show quite good fabrication tolerance. The manipulation of mid-infrared waves at the deep subwavelength scale using graphene plasmons may offer potential applications in tunable integrated nanophotonic devices and infrared sensing.
Collapse
|
22
|
Xu Y, Li F, Kang Z, Huang D, Zhang X, Tam HY, Wai PKA. Hybrid Graphene-Silicon Based Polarization-Insensitive Electro-Absorption Modulator with High-Modulation Efficiency and Ultra-Broad Bandwidth. NANOMATERIALS 2019; 9:nano9020157. [PMID: 30691206 PMCID: PMC6409800 DOI: 10.3390/nano9020157] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 12/02/2022]
Abstract
Polarization-insensitive modulation, i.e., overcoming the limit of conventional modulators operating under only a single-polarization state, is desirable for high-capacity on-chip optical interconnects. Here, we propose a hybrid graphene-silicon-based polarization-insensitive electro-absorption modulator (EAM) with high-modulation efficiency and ultra-broad bandwidth. The hybrid graphene-silicon waveguide is formed by leveraging multi-deposited and multi-transferred methods to enable light interaction with graphene layers in its intense field distribution region instead of the commonly used weak cladding region, thus resulting in enhanced light–graphene interaction. By optimizing the dimensions of all hybrid graphene-silicon waveguide layers, polarization-insensitive modulation is achieved with a modulation efficiency (ME) of ~1.11 dB/µm for both polarizations (ME discrepancy < 0.006 dB/µm), which outperforms that of previous reports. Based on this excellent modulation performance, we designed a hybrid graphene-silicon-based EAM with a length of only 20 µm. The modulation depth (MD) and insertion loss obtained were higher than 22 dB and lower than 0.23 dB at 1.55 µm, respectively, for both polarizations. Meanwhile, its allowable bandwidth can exceed 300 nm by keeping MD more than 20 dB and MD discrepancy less than 2 dB, simultaneously, and its electrical properties were also analyzed. Therefore, the proposed device can be applied in on-chip optical interconnects.
Collapse
Affiliation(s)
- Yin Xu
- Photonics Research Centre, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China.
| | - Feng Li
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China.
- Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| | - Zhe Kang
- Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| | - Dongmei Huang
- Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| | - Xianting Zhang
- Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| | - Hwa-Yaw Tam
- Photonics Research Centre, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| | - P K A Wai
- Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
| |
Collapse
|
23
|
Thomaschewski M, Yang Y, Bozhevolnyi SI. Ultra-compact branchless plasmonic interferometers. NANOSCALE 2018; 10:16178-16183. [PMID: 30118122 DOI: 10.1039/c8nr04213f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Miniaturization of functional optical devices and circuits is a key prerequisite for a myriad of applications ranging from biosensing to quantum information processing. This development has considerably been spurred by rapid developments within plasmonics exploiting its unprecedented ability to squeeze light into subwavelength scale. In this study, we investigate on-chip plasmonic systems allowing for synchronous excitation of multiple inputs and examine the interference between two adjacent excited channels. We present a branchless interferometer consisting of two parallel plasmonic waveguides that can be either selectively or coherently excited via ultra-compact antenna couplers. The total coupling efficiency is quantitatively characterized in a systematic manner and shown to exceed 15% for small waveguide separations, with the power distribution between the two waveguides being efficiently and dynamically shaped by adjusting the incident beam position. The presented design principle can readily be extended to other configurations, giving new perspectives for highly dense integrated plasmonic circuitry, optoelectronic devices, and sensing applications.
Collapse
Affiliation(s)
- Martin Thomaschewski
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | | | | |
Collapse
|
24
|
Wu Z, Xu Y. Design of a graphene-based dual-slot hybrid plasmonic electro-absorption modulator with high-modulation efficiency and broad optical bandwidth for on-chip communication. APPLIED OPTICS 2018; 57:3260-3267. [PMID: 29714316 DOI: 10.1364/ao.57.003260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The hybrid plasmonic effect with lower loss and comparable light confinement than surface plasmon polariton opens new avenues for strengthening light-matter interactions with low loss. Here, we propose and numerically analyze a graphene-based electro-absorption modulator (EAM) with high-modulation efficiency and broad optical bandwidth using a dual-slot hybrid plasmonic waveguide (HPW), which consists of a central dual-slot HPW connected with two taper transitions and two additional dual-slot HPWs for coupling it with the input and output silicon nanowires, where graphene layers are located at the bottom and top side of the whole dual-slot HPW region. By combining the huge light enhancement effect of the dual-slot HPW and graphene's tunable conductivity, we obtain a high-modulation efficiency (ME) of 1.76 dB/μm for the graphene-based dual-slot HPW (higher ME of 2.19 dB/μm can also be obtained). Based upon this promising result, we further design a graphene-based hybrid plasmonic EAM, achieving a modulation depth (MD) of 15.95 dB and insertion loss of 1.89 dB @1.55 μm, respectively, in a total length of only 10 μm, where its bandwidth can reach over 500 nm for keeping MD>15 dB; MD can also be improved by slightly increasing the device length or shrinking the waveguide thickness, showing strong advantages for applying it into on-chip high-performance silicon modulators.
Collapse
|