研究生: |
林庭生 Ting-Sheng Lin |
---|---|
論文名稱: |
低耦合光學天線陣列應用於矽光子積體化之LiDAR波束成形 Low-coupling Optical Antenna Array based Silicon Photonic Integration for LiDAR Beam Forming |
指導教授: |
徐世祥
Shih-Hsiang Hsu 林保宏 Pao-hung Lin |
口試委員: |
徐世祥
Shih-Hsiang Hsu 李三良 San-Liang Lee 邱華恭 Hua-Kung Chiu 林保宏 Pao-hung Lin |
學位類別: |
碩士 Master |
系所名稱: |
電資學院 - 電子工程系 Department of Electronic and Computer Engineering |
論文出版年: | 2020 |
畢業學年度: | 108 |
語文別: | 中文 |
論文頁數: | 91 |
中文關鍵詞: | 矽線波導 、光學相位陣列 、光達 |
外文關鍵詞: | Silicon waveguide, Optical phase array, LiDAR |
相關次數: | 點閱:531 下載:0 |
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在現今探測距離技術中,使用LiDAR在對於機器人、無人自駕車等等都佔有一席之地。而傳統LiDAR是以光學與機械式部件作為光束的掃描,在不考慮LiDAR的高價位之情況,其在嚴峻的工作環境下,掃描速度、穩定性及體積小特性需要被顯著地提升,因此快速掃描與積體化的LiDAR是未來的發展方向。透過矽光子積體電路之技術將LiDAR微小化,且為了提升轉向角及減少熱控制器的數量,需將天線陣列之間的間距設計在半波長附近,並使用聯級熱相移器,使得可視場(Field of View)放大至接近180°左右,同時大幅減少熱控制器數量。但因天線陣列間距設計在半波長附近,導致波導非常密集,會衍生出串擾(Crosstalk)的問題,因此本論文將會深入的討論矽線波導與光學天線之間如何降低耦合及相位串擾對於波束成形遠場之影響。
為了減少一維與二維LiDAR過於複雜的熱控制器之數量,我們使用聯級熱移相器陣列。因為可視場之角度提升使得天線陣列間距非常密集,波導之間會有串擾的問題,所以欲降低一維波導天線陣列間的串擾,本論文設計了一維線寬變化的波導天線陣列。由於聯級熱相移器陣列為同時調制多根天線之相位,其無法直接調制因線寬變化而導致天線陣列間之相位差,因此我們額外加入錐形波導做相位補償。本論文最後將一維天線陣列的間距縮小,使LiDAR的可視場達到110°;二維低耦合天線陣列為使用矽帶光柵結構來降低傳統二維光學天線陣列之間的串擾,該串擾之降低幅度約為3-dB。其中二維光學天線陣列的間距為1μm,根據理論可得知,可視場在1μm的天線陣列間距下約為110°。
In modern detection and ranging technology, the light detection and ranging (LiDAR) systems are used in almost every robotics and autonomous vehicles. Free-space optics and mechanical components are typically utilized to steer the beam in LiDAR, which is unstable, bulky, expensive, and not suitable in a harsh environment. Moreover, the fabrication maturity in silicon photonic integrated circuit could miniaturize the photonic system. Thus, a high scan rate and solid-state LiDAR on silicon-on-insulator (SOI) platforms are becoming trends currently. To increase the output steering angle and reduce the controller number in an antenna array, the antenna spacing should be as close as the half operating wavelength. The cascade thermal phase shifter makes the field of view (FoV) to approximate 180° while the controller number is significantly reduced. However, if the antenna spacing is too close, the crosstalk between the antenna array will increase. In this thesis, it will be demonstrated to reduce the coupling influence and phase crosstalk between the optical antenna for far-field beamforming.
To reduce overly complicated heat controllers, a cascaded thermal phase shifter array is used. For horizontal steering, the antenna spacing is as close as half of the operating wavelength and shows the low crosstalk using index-mismatched waveguides and phase-compensation. Moreover, the same output optical waveguide mode needs to be further considered to demonstrate the grating lobe-free beam steering. And its FoV experimentally shows 110°.
For two-dimensional beam forming, the low coupling between antenna array consists of the close half-operating-wavelength spacing integrated with a silicon-strip-grating structure. Then the 8 channel array with a 1-μm pitch is simulated through finite difference time domain (FDTD) methods and shows a 3-dB reduction in array crosstalk and 5-dB improvement in grating lobe at a 30° steering angle.
[1] M. Himmelsbach, A. Müller, T. Luettel, and H.-J. Wünsche, “LIDAR-based 3D object perception,” Proceedings of 1st international workshop on cognition for technical systems 1, 2008.
[2] K. Van Acoleyen, W. Bogaerts, J. Jágerská, N. Le Thomas, R. Houdré and R. Baets, "Off-chip beam steering with a one-dimensional optical phased array on silicon-on-insulator", Optics Letters, vol. 34, no. 9, p. 1477, 2009.
[3] M. R. Kossey, N. MacFarlane, K. G. Petrillo, C. Rizk, and A. C. Foster, "Silicon Micro/Nanophotonic Optical Phased Arrays for Beam Steering," in Advanced Photonics, OSA Technical Digest, paper IM3B.5, 2018
[4] S. Pinna, B. Song, L. A. Coldren, and J. Klamkin, "Vernier Transceiver Architecture for Side-Lobe-Free and High-Entendue LiDAR," in Conference on Lasers and Electro-Optics, OSA Technical Digest, paper ATu3R.3, 2018
[5] M. Kossey, C. Rizk and A. Foster, "End-fire silicon optical phased array with half-wavelength spacing", APL Photonics, vol. 3, no. 1, p. 011301, 2018.
[6] K. Shang, C. Qin, Y. Zhang, G. Liu, X. Xian, S. Feng and S. B. Yoo, "Uniform emission, constant wavevector silicon grating surface emitter for beam steering with ultra-sharp instantaneous field-of-view", Optics Express, vol. 25, no. 17, p. 19655, 2017.
[7] A. Yaacobi, J. Sun, M. Moresco, G. Leake, D. Coolbaugh and M. Watts, "Integrated phased array for wide-angle beam steering", Optics Letters, vol. 39, no. 15, p. 4575, 2014.
[8] J. C. Hulme, J. K. Doylend, M. J. R. Heck, J. D. Peters, M. L. Davenport, J. T. Bovington, L. A. Coldren, and J. E. Bowers, "Fully integrated hybrid silicon two dimensional beam scanner", Optics Express, vol. 23, no. 5, p. 5861, 2015.
[9] T. Komljenovic, R. Helkey, L. Coldren and J. Bowers, "Sparse aperiodic arrays for optical beam forming and LIDAR", Optics Express, vol. 25, no. 3, p. 2511, 2017.
[10] C. V. Poulton, M. J. Byrd, M. Raval, Z. Su, N. Li, E. Timurdogan, D. Coolbaugh, D. Vermeulen, and M. R. Watts, "Large-scale silicon nitride nanophotonic phased arrays at infrared and visible wavelengths", Optics Letters, vol. 42, no. 1, p. 21, 2016.
[11] T. Komljenovic and P. Pintus, "On-chip calibration and control of optical phased arrays", Optics Express, vol. 26, no. 3, p. 3199, 2018.
[12] D. Zhuang, L. Zhagn, X. Han, Y. Li, Y. Li, X. Liu, F. Gao, and J. Song, "Omnidirectional beam steering using aperiodic optical phased array with high error margin", Optics Express, vol. 26, no. 15, p. 19154, 2018.
[13] C. Phare, M. Shin, J. Sharma, S. Ahasan, H. Krishnaswamy and M. Lipson, "Silicon Optical Phased Array with Grating Lobe-Free Beam Formation Over 180 Degree Field of View", Conference on Lasers and Electro-Optics, 2018.
[14] D. N. Hutchison, J. S., Jonathan K. Doylend, R. Kumar, J. Heck, W. Kim, C. T. Phare, A. Feshali, and H. Rong, "High-resolution aliasing-free optical beam steering", Optica, vol. 3, no. 8, p. 887, 2016.
[15] C. Poulton, P. Russo, E. Timurdogan, M. Whitson, M. Byrd, E. Hosseini, B. Moss, Z. Su, D. Vermeulen, and M. Watts, "High-Performance Integrated Optical Phased Arrays for Chip-Scale Beam Steering and LiDAR", Conference on Lasers and Electro-Optics, 2018.
[16] S. Miller, C. Phare, Y. Chang, X. Ji, O. Gordillo, A. Mohanty, S. Roberts, M. Shin, B. Stern, M. Zadka, and M. Lipson, "512-Element Actively Steered Silicon Phased Array for Low-Power LIDAR", Conference on Lasers and Electro-Optics, 2018.
[17] C. R. Doerr, M. Cappuzzo, E. Chen, A.Wong-Foy, L. Gomez, A. Griffin, and L. Buhl, “Bending of a planar lightwave circuit 2 × 2 coupler to desensitize it to wavelength, polarization, and fabrication changes,” IEEE Photonics Technology Letters, Vol. 17, No. 6, p. 1211, 2005.
[18] H. Morino, T. Maruyama and K. Iiyama, “Reduction of wavelength dependence of coupling characteristics using Si optical waveguide curved directional coupler,” Journal of Lightwave Technology, Vol. 32, No. 12, p. 2188, 2014.
[19] S. Chen, Y. Shi, S. He, and D. Dai, “Low-loss and broadband 2 × 2 silicon thermo-optic Mach-Zehnder switch with bent directional couplers,” Optics Letters, Vol. 41, No. 4, p. 836, 2016.
[20] Y. Wang, Z. Lu, M. Ma, H. Yun, F. Zhang, N. A. F. Jaeger, and L. Chrostowski, “Compact broadband directional couplers using subwavelength gratings,” IEEE Photonics Technology Letters, Vol. 8, No. 3, p. 7101408, 2016.
[21] R. A. Soref , J. Schmidtchen and K. Petermann, “Large single-mode rib waveguides in GeSi-Si and Si-on-SiO2,” IEEE Journal of Quantum Electronics, Vol. 27, No. 8, p. 1971, 1991.
[22] S. P. Chan, C. E. Png, S. T. Lim, G. T. Reed, and V. M. N. Passaro, “Single-mode and polarization-independent Silicon-on-Insulator waveguides with small cross section,” Journal of Lightwave Technology, Vol. 23, No. 6, p. 2103, 2005.
[23] T. Aalto, Microphotonic silicon waveguide components: VTT Technical Research Centre of Finland, 2004.
[24] K. W. Ang, G.Q. Lo , “Avalanche photodiodes: Si charge avalanche enhances APD sensitivity beyond 100 GHz,” Laser Focus World, Vol. 46, No. 8, p. 41, 2010.
[25] P. Dumon, W. Bogaerts, V. Wiaux, J. Wouters, S. Beckx, J.V. Campenhout, D. Taillaert, B. Luyssaert, P. Bienstman, D.V. Thourhout, R. Baets, “Low-loss SOI photonic wires and ring resonators fabricated with deep UV lithography,” IEEE Photonics Technology Letters, Vol. 16, No. 5, p. 1328, 2004.
[26] Y. Hbino, “Recent advances in high-density and large-scale AWG multi/demultiplexers with higher index-contrast silica-based PLCs,” IEEE Journal of Selected Topics in Quantum Electronics, Vol. 8, No. 6, p. 1090, 2002.
[27] Sakai, G. Hara, and T. Baba, “Sharply bent optical waveguide on silicon-on-insulator substrate,” Proceedings of SPIE, Vol. 4283, p. 610, 2001.
[28] E. A. J. Marcatili, “Bends in optical dielectric guides,” The Bell System Technical Journal, p. 2103, 1969.
[29] M. Heiblum, and J. H. Harris, “Analysis of curved optical waveguides by conformal transformation,” IEEE Journal of Quantum Electronics, Vol. QE-11, No. 2, p. 75, 1975.
[30] Y. A. Vlasov, and S. J. McNab, “Losses in single-mode silicon-on-insulator strip waveguides and bends,” Optics Express, Vol. 12, No. 8, p. 1622, 2004.
[31] V. Subramaniam, G. N. D. Brabander, D. H. Naghski, and J. T. Boyd, “Measurement of mode field profiles and bending and transition losses in curved optical channel waveguides,” Journal of Lightwave Technology, Vol. 15, No. 6, p. 990, 1997.
[32] K. K. Lee, D. R. Lim, H.C. Luan, A. Agarwal, J. Foresi, and L. C. Kimerling, “Effect of size and roughness on light transmission in a Si/SiO2 waveguide: experiments and model,” Applied Physics Letters, Vol. 77, No. 11, p. 1617, 2000.
[33] D. Marcuse, “Mode conversion caused by surface imperfections of a dielectric slab waveguide,” Bell System Technical Journal, Vol. 48, No. 10, p. 3187, 1969.
[34] F. P. Payne, J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Optical and Quantum Electronics, Vol. 26, p. 977, 1994.
[35] F. Grillot, L. Vivien, S. Laval, D. Pascal, and E. Cassan, "Size influence on the propagation loss induced by sidewall roughness in ultrasmall SOI waveguides," IEEE Photonics Technology Letters, Vol. 16, p. 1661, 2004.
[36] M. Dakss, L. Kuhn, P. Heidrich and B. Scott, "ERRATA: GRATING COUPLER FOR EFFICIENT EXCITATION OF OPTICAL GUIDED WAVES IN THIN FILMS", Applied Physics Letters, vol. 17, no. 6, p. 268, 1970.
[37] J. W. Goodman, “Introduction to fourier optics” (2004, 3rd edition).
[38] R. Waldhäusl, B. Schnabel, P. Dannberg, E. Kley, A. Bräuer and W. Karthe, "Efficient Coupling into Polymer Waveguides by Gratings", Applied Optics, vol. 36, no. 36, p. 9383, 1997.
[39] F. Van Laere, T. Claes, J. Schrauwen, S. Scheerlinck, W. Bogaerts, D. Taillaert, L. O'Faolain, D. Van Thourhout and R. Baets, "Compact Focusing Grating Couplers for Silicon-on-Insulator Integrated Circuits", IEEE Photonics Technology Letters, vol. 19, no. 23, p. 1919, 2007.
[40] K.Van Acoleyen, K. Komorowska, W. Bogaerts, and R. Baets, "One-Dimensional Off-Chip Beam Steering and Shaping Using Optical Phased Arrays on Silicon-on-Insulator ", Journal of Lightwave Technology, 29(23), p.3500, 2011.
[41] S. Zhu et al., "Silicon Nitride Optical Phased Arrays with Cascaded Phase
Shifters for Easy and Effective Electronic Control," in CLEO: Applications
and Technology, 2019: Optical Society of America, p. AW4K. 5.
[42] R. Zhang, T. Lin, W. Liu, S. Hsu, and C. Chang, "Grating Lobe-Free Beam
Steering through Optical Phase Array Using Phase-Compensated Two Index-Mismatched Silicon Wires-Based Emitters", Applied Sciences, 10(4), p.1225, 2020.
[43] Y. Bian, Q. Ren, L. Kang, Y. Qin, P. Werner and D. Werner, "Efficient Cross-
talk Reduction of Nanophotonic Circuits Enabled by Fabrication Friendly Periodic Silicon Strip Arrays", Scientific Reports, vol. 7, no. 1, 2017. Available: 10.1038/s41598-017-16096-9.