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Gandolfi M, Carletti L, Tognazzi A, Cino AC, De Angelis C, Guasoni M. Near to short wave infrared light generation through AlGaAs-on-insulator nanoantennas. OPTICS EXPRESS 2023; 31:31051-31060. [PMID: 37710633 DOI: 10.1364/oe.498592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 07/30/2023] [Indexed: 09/16/2023]
Abstract
AlGaAs-on-insulator (AlGaAs-OI) has recently emerged as a promising platform for nonlinear optics at the nanoscale. Among the most remarkable outcomes, second-harmonic generation (SHG) in the visible/near infrared spectral region has been demonstrated in AlGaAs-OI nanoantennas (NAs). In order to extend the nonlinear frequency generation towards the short wave infrared window, in this work we propose and demonstrate via numerical simulations difference frequency generation (DFG) in AlGaAs-OI NAs. The NA geometry is finely adjusted in order to obtain simultaneous optical resonances at the pump, signal and idler wavelengths, which results in an efficient DFG with conversion efficiencies up to 0.01%. Our investigation includes the study of the robustness against random variations of the NA geometry that may occur at fabrication stage. Overall, these outcomes identify what we believe to be a new potential and yet unexplored application of AlGaAs-OI NAs as compact devices for the generation and control of the radiation pattern in the near to short infrared spectral region.
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2
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Thomas R, Li H, Laverock J, Balram KC. Quantifying and mitigating optical surface loss in suspended GaAs photonic integrated circuits. OPTICS LETTERS 2023; 48:3861-3864. [PMID: 37527068 DOI: 10.1364/ol.492505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/19/2023] [Indexed: 08/03/2023]
Abstract
Understanding and mitigating optical loss is critical to the development of high-performance photonic integrated circuits (PICs). In particular, in high refractive index contrast compound semiconductor (III-V) PICs, surface absorption and scattering can be a significant loss mechanism, and needs to be suppressed. Here, we quantify the optical propagation loss due to surface state absorption in a suspended GaAs PIC platform, probe its origins using x-ray photoemission spectroscopy and spectroscopic ellipsometry, and show that it can be mitigated by surface passivation using alumina (Al2O3).
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3
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Wu L, Xie W, Chen HJ, Colburn K, Xiang C, Chang L, Jin W, Liu JY, Yu Y, Yamamoto Y, Bowers JE, Suh MG, Vahala KJ. AlGaAs soliton microcombs at room temperature. OPTICS LETTERS 2023; 48:3853-3856. [PMID: 37527066 DOI: 10.1364/ol.484552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/21/2023] [Indexed: 08/03/2023]
Abstract
Soliton mode locking in high-Q microcavities provides a way to integrate frequency comb systems. Among material platforms, AlGaAs has one of the largest optical nonlinearity coefficients, and is advantageous for low-pump-threshold comb generation. However, AlGaAs also has a very large thermo-optic effect that destabilizes soliton formation, and femtosecond soliton pulse generation has only been possible at cryogenic temperatures. Here, soliton generation in AlGaAs microresonators at room temperature is reported for the first time, to the best of our knowledge. The destabilizing thermo-optic effect is shown to instead provide stability in the high-repetition-rate soliton regime (corresponding to a large, normalized second-order dispersion parameter D2/κ). Single soliton and soliton crystal generation with sub-milliwatt optical pump power are demonstrated. The generality of this approach is verified in a high-Q silica microtoroid where manual tuning into the soliton regime is demonstrated. Besides the advantages of large optical nonlinearity, these AlGaAs devices are natural candidates for integration with semiconductor pump lasers. Furthermore, the approach should generalize to any high-Q resonator material platform.
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4
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Shen B, Shu H, Xie W, Chen R, Liu Z, Ge Z, Zhang X, Wang Y, Zhang Y, Cheng B, Yu S, Chang L, Wang X. Harnessing microcomb-based parallel chaos for random number generation and optical decision making. Nat Commun 2023; 14:4590. [PMID: 37524697 PMCID: PMC10390475 DOI: 10.1038/s41467-023-40152-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 07/14/2023] [Indexed: 08/02/2023] Open
Abstract
Optical chaos is vital for various applications such as private communication, encryption, anti-interference sensing, and reinforcement learning. Chaotic microcombs have emerged as promising sources for generating massive optical chaos. However, their inter-channel correlation behavior remains elusive, limiting their potential for on-chip parallel chaotic systems with high throughput. In this study, we present massively parallel chaos based on chaotic microcombs and high-nonlinearity AlGaAsOI platforms. We demonstrate the feasibility of generating parallel chaotic signals with inter-channel correlation <0.04 and a high random number generation rate of 3.84 Tbps. We further show the application of our approach by demonstrating a 15-channel integrated random bit generator with a 20 Gbps channel rate using silicon photonic chips. Additionally, we achieved a scalable decision-making accelerator for up to 256-armed bandit problems. Our work opens new possibilities for chaos-based information processing systems using integrated photonics, and potentially can revolutionize the current architecture of communication, sensing and computations.
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Affiliation(s)
- Bitao Shen
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Haowen Shu
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China.
| | - Weiqiang Xie
- Department of Electronic Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Ruixuan Chen
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Zhi Liu
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Zhangfeng Ge
- Peking University Yangtze Delta Institute of Optoelectronics, 226010, Nantong, China
| | - Xuguang Zhang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Yimeng Wang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Yunhao Zhang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Buwen Cheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shaohua Yu
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
- Peng Cheng Laboratory, 518055, Shenzhen, China
| | - Lin Chang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China.
- Frontiers Science Center for Nano-optoelectronics, Peking University, 100871, Beijing, China.
| | - Xingjun Wang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China.
- Peking University Yangtze Delta Institute of Optoelectronics, 226010, Nantong, China.
- Peng Cheng Laboratory, 518055, Shenzhen, China.
- Frontiers Science Center for Nano-optoelectronics, Peking University, 100871, Beijing, China.
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5
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Liu P, Wen H, Ren L, Shi L, Zhang X. χ (2) nonlinear photonics in integrated microresonators. FRONTIERS OF OPTOELECTRONICS 2023; 16:18. [PMID: 37460874 DOI: 10.1007/s12200-023-00073-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/22/2023] [Indexed: 07/20/2023]
Abstract
Second-order (χ(2)) optical nonlinearity is one of the most common mechanisms for modulating and generating coherent light in photonic devices. Due to strong photon confinement and long photon lifetime, integrated microresonators have emerged as an ideal platform for investigation of nonlinear optical effects. However, existing silicon-based materials lack a χ(2) response due to their centrosymmetric structures. A variety of novel material platforms possessing χ(2) nonlinearity have been developed over the past two decades. This review comprehensively summarizes the progress of second-order nonlinear optical effects in integrated microresonators. First, the basic principles of χ(2) nonlinear effects are introduced. Afterward, we highlight the commonly used χ(2) nonlinear optical materials, including their material properties and respective functional devices. We also discuss the prospects and challenges of utilizing χ(2) nonlinearity in the field of integrated microcavity photonics.
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Affiliation(s)
- Pengfei Liu
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hao Wen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Linhao Ren
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lei Shi
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
- Optics Valley Laboratory, Wuhan, 430074, China.
| | - Xinliang Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Wuhan, 430074, China
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6
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Kamel AN, Pu M, Yvind K. Surface defect effects in AlGaAs-on-Insulator photonic waveguides. OPTICS EXPRESS 2023; 31:20424-20439. [PMID: 37381437 DOI: 10.1364/oe.490043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/18/2023] [Indexed: 06/30/2023]
Abstract
We report on our study of optical losses due to sub-band-gap absorption in AlGaAs-on-Insulator photonic nano-waveguides. Via numerical simulations and optical pump-probe measurements, we find that there is significant free carrier capture and release by defect states. Our measurements of the absorption of these defects point to the prevalence of the well-studied EL2 defect, which forms near oxidized (Al)GaAs surfaces. We couple our experimental data with numerical and analytical models to extract important parameters related to surface states, namely the coefficients of absorption, surface trap density and free carrier lifetime.
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7
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Lao C, Jin X, Chang L, Wang H, Lv Z, Xie W, Shu H, Wang X, Bowers JE, Yang QF. Quantum decoherence of dark pulses in optical microresonators. Nat Commun 2023; 14:1802. [PMID: 37002215 PMCID: PMC10066214 DOI: 10.1038/s41467-023-37475-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/16/2023] [Indexed: 04/03/2023] Open
Abstract
Quantum fluctuations disrupt the cyclic motions of dissipative Kerr solitons (DKSs) in nonlinear optical microresonators and consequently cause timing jitter of the emitted pulse trains. This problem is translated to the performance of several applications that employ DKSs as compact frequency comb sources. Recently, device manufacturing and noise reduction technologies have advanced to unveil the quantum properties of DKSs. Here we investigate the quantum decoherence of DKSs existing in normal-dispersion microresonators known as dark pulses. By virtue of the very large material nonlinearity, we directly observe the quantum decoherence of dark pulses in an AlGaAs-on-insulator microresonator, and the underlying dynamical processes are resolved by injecting stochastic photons into the microresonators. Moreover, phase correlation measurements show that the uniformity of comb spacing of quantum-limited dark pulses is better than 1.2 × 10-16 and 2.5 × 10-13 when normalized to the optical carrier frequencies and repetition frequencies, respectively. Comparing DKSs generated in different material platforms explicitly confirms the advantages of dark pulses over bright solitons in terms of quantum-limited coherence. Our work establishes a critical performance assessment of DKSs, providing guidelines for coherence engineering of chip-scale optical frequency combs.
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Affiliation(s)
- Chenghao Lao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Xing Jin
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Lin Chang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Heming Wang
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Zhe Lv
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Weiqiang Xie
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA
- State Key Lab of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Haowen Shu
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Xingjun Wang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - John E Bowers
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA.
| | - Qi-Fan Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
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8
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Wang PH, Lee TH, Huang WH. Fabrication of tapered waveguides by i-line UV lithography for flexible coupling control. OPTICS EXPRESS 2023; 31:4281-4290. [PMID: 36785400 DOI: 10.1364/oe.473623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/01/2022] [Indexed: 06/18/2023]
Abstract
A tapered bus-waveguide is demonstrated to enhance the waveguide-to-cavity coupling by mass-productive, cost-effective i-line UV lithography. Through enlarging the overlap between the evanescent wave and waveguide resonator, we experimentally show that the coupling strength of silicon nitride waveguides can be 7 times stronger than the conventional coupling of a uniform, straight bus-waveguide. For the first time, strong over-coupling is identified at a 400 nm gap and quality factor ≈ 105 without elongating the coupling length. This design relieves the fabrication limits and provides the flexibility for coupling control, especially in the strongly over-coupled regime with i-line UV lithography.
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9
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Jia L, Wu J, Zhang Y, Qu Y, Jia B, Moss DJ. Third-Order Optical Nonlinearities of 2D Materials at Telecommunications Wavelengths. MICROMACHINES 2023; 14:307. [PMID: 36838007 PMCID: PMC9962682 DOI: 10.3390/mi14020307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/14/2023] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
All-optical signal processing based on nonlinear optical devices is promising for ultrafast information processing in optical communication systems. Recent advances in two-dimensional (2D) layered materials with unique structures and distinctive properties have opened up new avenues for nonlinear optics and the fabrication of related devices with high performance. This paper reviews the recent advances in research on third-order optical nonlinearities of 2D materials, focusing on all-optical processing applications in the optical telecommunications band near 1550 nm. First, we provide an overview of the material properties of different 2D materials. Next, we review different methods for characterizing the third-order optical nonlinearities of 2D materials, including the Z-scan technique, third-harmonic generation (THG) measurement, and hybrid device characterization, together with a summary of the measured n2 values in the telecommunications band. Finally, the current challenges and future perspectives are discussed.
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Affiliation(s)
- Linnan Jia
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Jiayang Wu
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Yuning Zhang
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Yang Qu
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Baohua Jia
- School of Science, RMIT University, Melbourne, VIC 3001, Australia
- Australian Research Council (ARC) Industrial Transformation Training, Centre in Surface Engineering for Advanced Materials (SEAM), RMIT University, Melbourne, VIC 3000, Australia
| | - David J. Moss
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
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10
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Nigro D, Clementi M, Brés CS, Liscidini M, Gerace D. Single-photon nonlinearities and blockade from a strongly driven photonic molecule. OPTICS LETTERS 2022; 47:5348-5351. [PMID: 36240359 DOI: 10.1364/ol.468546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Achieving the regime of single-photon nonlinearities in photonic devices by just exploiting the intrinsic high-order susceptibilities of conventional materials would open the door to practical semiconductor-based quantum photonic technologies. Here we show that this regime can be achieved in a triply resonant integrated photonic device made of two coupled ring resonators, in a material platform displaying an intrinsic third-order nonlinearity. By strongly driving one of the three resonances of the system, a weak coherent probe at one of the others results in a strongly suppressed two-photon probability at the output, evidenced by an antibunched second-order correlation function at zero-time delay under continuous wave driving.
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11
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Zeng D, Liu Q, Mei C, Li H, Huang Q, Zhang X. Demonstration of Ultra-High-Q Silicon Microring Resonators for Nonlinear Integrated Photonics. MICROMACHINES 2022; 13:mi13071155. [PMID: 35888971 PMCID: PMC9322067 DOI: 10.3390/mi13071155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 11/25/2022]
Abstract
A reflowing photoresist and oxidation smoothing process is used to fabricate ultra-high-Q silicon microring resonators based on multimode rib waveguides. Over a wide range of wavelengths near 1550 nm, the average Q-factor of a ring with 1.2-μm-wide waveguides reaches up to 1.17 × 106, with a waveguide loss of approximately 0.28 dB/cm. For a resonator with 1.5-μm-wide waveguides, the average Q-factor reaches 1.20 × 106, and the waveguide loss is 0.27 dB/cm. Moreover, we theoretically and experimentally show that a reduction in the waveguide loss significantly improves the conversion efficiency of four-wave mixing. A high four-wave mixing conversion efficiency of −17.0 dB is achieved at a pump power of 6.50 dBm.
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12
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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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13
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Probing material absorption and optical nonlinearity of integrated photonic materials. Nat Commun 2022; 13:3323. [PMID: 35680923 PMCID: PMC9184588 DOI: 10.1038/s41467-022-30966-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 05/26/2022] [Indexed: 11/19/2022] Open
Abstract
Optical microresonators with high quality (Q) factors are essential to a wide range of integrated photonic devices. Steady efforts have been directed towards increasing microresonator Q factors across a variety of platforms. With success in reducing microfabrication process-related optical loss as a limitation of Q, the ultimate attainable Q, as determined solely by the constituent microresonator material absorption, has come into focus. Here, we report measurements of the material-limited Q factors in several photonic material platforms. High-Q microresonators are fabricated from thin films of SiO2, Si3N4, Al0.2Ga0.8As, and Ta2O5. By using cavity-enhanced photothermal spectroscopy, the material-limited Q is determined. The method simultaneously measures the Kerr nonlinearity in each material and reveals how material nonlinearity and ultimate Q vary in a complementary fashion across photonic materials. Besides guiding microresonator design and material development in four material platforms, the results help establish performance limits in future photonic integrated systems. Optical absorption and nonlinear index are important performance drivers in devices like microcombs. Here the authors use resonance-enhanced nonlinear spectroscopy to characterize absorption limits and nonlinear index for some integrated photonic materials.
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Rukerandanga F, Musyoki S, Ataro EO. 3D design and analysis of an electro-optically tunable athermal and polarization-insensitive ring resonator-based add-drop filter for DWDM systems. Heliyon 2022; 8:e09567. [PMID: 35663458 PMCID: PMC9160769 DOI: 10.1016/j.heliyon.2022.e09567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/07/2022] [Accepted: 05/25/2022] [Indexed: 11/06/2022] Open
Abstract
Dense Wavelength Division Multiplexing system-based optical networks are currently the most appropriate solutions for all-optical networks that efficiently utilize the large bandwidth offered by optical fiber networks. Tunable ring resonator-based filters are highly attractive owing to their bandwidth and channel tunability, high spectral selectivity, low losses, low power consumption, and compactness; thus they are very good candidates for optical integrated circuits at a very large scale. We used titanium oxide and silicon oxide as the upper-cladding and under-cladding materials, respectively, around a silicon-rich nitride core to design an electro-optically tunable, polarization-insensitive, and thermally resilient sixth-order add-drop optical filter in the L-band (1565 nm-1625 nm). A thin film of lithium niobate added on the top of silicon oxide was used to enhance the tunability of the filter. A 3D multiphysics approach considering thermo-optic, and stress-optical effects while minimizing the polarization rotation has been adopted to solve the electromagnetic problem in a filter that can accommodate arbitrary Transverse Electric and Transverse Magnetic polarized optical signals. The device has a bandwidth of 50 GHz (linewidth of 0.4 nm) at a resonant wavelength of 1575.4 nm, an extended FSR of 2.512 THz, and losses of 0.82 dB in the bandpass. The filter is ultra-compact with a footprint of 15μm×160μm. We achieved a high-quality factor of 3250, a tunability efficiency of 8.95 pm/V, and a finesse of 31. To the best of our knowledge, it is the first time a complementary metal-oxide-semiconductor-compatible, electro-optically tunable, athermal, polarization-insensitive high order add-drop filter in the L-band with a top-flat response in the passband, and with an extended FSR has been designed for Dense Wavelength Division Multiplexing systems.
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Abstract
Microcombs have sparked a surge of applications over the past decade, ranging from optical communications to metrology1–4. Despite their diverse deployment, most microcomb-based systems rely on a large amount of bulky elements and equipment to fulfil their desired functions, which is complicated, expensive and power consuming. By contrast, foundry-based silicon photonics (SiPh) has had remarkable success in providing versatile functionality in a scalable and low-cost manner5–7, but its available chip-based light sources lack the capacity for parallelization, which limits the scope of SiPh applications. Here we combine these two technologies by using a power-efficient and operationally simple aluminium-gallium-arsenide-on-insulator microcomb source to drive complementary metal–oxide–semiconductor SiPh engines. We present two important chip-scale photonic systems for optical data transmission and microwave photonics, respectively. A microcomb-based integrated photonic data link is demonstrated, based on a pulse-amplitude four-level modulation scheme with a two-terabit-per-second aggregate rate, and a highly reconfigurable microwave photonic filter with a high level of integration is constructed using a time-stretch approach. Such synergy of a microcomb and SiPh integrated components is an essential step towards the next generation of fully integrated photonic systems. A simple and power-efficient microcomb source is used to drive complementary metal–oxide–semiconductor silicon photonic engines, a step towards the next generation of fully integrated photonic systems.
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