A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR
Frequency-modulated continuous-wave (FMCW) LiDAR systems are drawing increasing interest due to their potential applications in autonomous driving, machine perception, rapid prototyping, and medical diagnostics. The nonlinearity of a laser’s input-output transfer function can degrade the...
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| Format: | Article |
| Language: | English |
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IEEE
2021-01-01
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| Series: | IEEE Open Journal of the Solid-State Circuits Society |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/9576527/ |
| _version_ | 1797197372420259840 |
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| author | Ali Binaie Sohail Ahasan Harish Krishnaswamy |
| author_facet | Ali Binaie Sohail Ahasan Harish Krishnaswamy |
| author_sort | Ali Binaie |
| collection | DOAJ |
| description | Frequency-modulated continuous-wave (FMCW) LiDAR systems are drawing increasing interest due to their potential applications in autonomous driving, machine perception, rapid prototyping, and medical diagnostics. The nonlinearity of a laser’s input-output transfer function can degrade the performance of an FMCW LiDAR. However, traditional discrete-time electro-optical phase-locked loops (DT-EOPLLs) face an unfavorable trade-off between chirp bandwidth and Mach-Zehnder delay. We present an integrated continuous-time electro-optic phase-locked loop (CT-EOPLL) to address this problem. The proposed EOPLL is very wideband, with its loop bandwidth equal to its reference frequency. This feature enables it to relax the trade-off between chirp bandwidth and Mach-Zehnder (MZ) delay by <inline-formula> <tex-math notation="LaTeX">$10\times $ </tex-math></inline-formula> in dB scale, which consequently reduces the area and loss associated with the silicon photonic delay implementation. It also does not suffer from the challenging issue of spurs in wideband PLLs because it features image and harmonic spur suppression in the loop using single-sideband (SSB) and harmonic-reject (HR) mixing techniques. The electrical part of this EOPLL is implemented in 65nm CMOS technology, and its optical integrated circuit is fabricated using a silicon photonic process. Featuring more than 25dB of suppression of the highest spur, this EOPLL is utilized in a high precision LiDAR sensor that shows an RMS depth precision of <inline-formula> <tex-math notation="LaTeX">$558~\mu \text{m}$ </tex-math></inline-formula> at 2m distance, and a 9.4mm RMS depth resolution at ranges exceeding 3.3m. |
| first_indexed | 2024-04-24T06:42:55Z |
| format | Article |
| id | doaj.art-11b0ad60d69848899321a1250acde223 |
| institution | Directory Open Access Journal |
| issn | 2644-1349 |
| language | English |
| last_indexed | 2024-04-24T06:42:55Z |
| publishDate | 2021-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Open Journal of the Solid-State Circuits Society |
| spelling | doaj.art-11b0ad60d69848899321a1250acde2232024-04-22T20:40:01ZengIEEEIEEE Open Journal of the Solid-State Circuits Society2644-13492021-01-01123524610.1109/OJSSCS.2021.31202439576527A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDARAli Binaie0https://orcid.org/0000-0002-5021-9508Sohail Ahasan1https://orcid.org/0000-0003-2147-2632Harish Krishnaswamy2https://orcid.org/0000-0002-6325-8872Department of Electrical Engineering, Columbia University, New York, NY, USADepartment of Electrical Engineering, Columbia University, New York, NY, USADepartment of Electrical Engineering, Columbia University, New York, NY, USAFrequency-modulated continuous-wave (FMCW) LiDAR systems are drawing increasing interest due to their potential applications in autonomous driving, machine perception, rapid prototyping, and medical diagnostics. The nonlinearity of a laser’s input-output transfer function can degrade the performance of an FMCW LiDAR. However, traditional discrete-time electro-optical phase-locked loops (DT-EOPLLs) face an unfavorable trade-off between chirp bandwidth and Mach-Zehnder delay. We present an integrated continuous-time electro-optic phase-locked loop (CT-EOPLL) to address this problem. The proposed EOPLL is very wideband, with its loop bandwidth equal to its reference frequency. This feature enables it to relax the trade-off between chirp bandwidth and Mach-Zehnder (MZ) delay by <inline-formula> <tex-math notation="LaTeX">$10\times $ </tex-math></inline-formula> in dB scale, which consequently reduces the area and loss associated with the silicon photonic delay implementation. It also does not suffer from the challenging issue of spurs in wideband PLLs because it features image and harmonic spur suppression in the loop using single-sideband (SSB) and harmonic-reject (HR) mixing techniques. The electrical part of this EOPLL is implemented in 65nm CMOS technology, and its optical integrated circuit is fabricated using a silicon photonic process. Featuring more than 25dB of suppression of the highest spur, this EOPLL is utilized in a high precision LiDAR sensor that shows an RMS depth precision of <inline-formula> <tex-math notation="LaTeX">$558~\mu \text{m}$ </tex-math></inline-formula> at 2m distance, and a 9.4mm RMS depth resolution at ranges exceeding 3.3m.https://ieeexplore.ieee.org/document/9576527/Electro-optics phase-locked loop (EOPLL)LiDARelectro optical systemfrequency-modulated continuous wave (FMCW) LiDARlaser nonlinearityoptical ranging |
| spellingShingle | Ali Binaie Sohail Ahasan Harish Krishnaswamy A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR IEEE Open Journal of the Solid-State Circuits Society Electro-optics phase-locked loop (EOPLL) LiDAR electro optical system frequency-modulated continuous wave (FMCW) LiDAR laser nonlinearity optical ranging |
| title | A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR |
| title_full | A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR |
| title_fullStr | A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR |
| title_full_unstemmed | A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR |
| title_short | A Spurless and Wideband Continuous-Time Electro-Optical Phase Locked Loop (CT-EOPLL) for High Performance LiDAR |
| title_sort | spurless and wideband continuous time electro optical phase locked loop ct eopll for high performance lidar |
| topic | Electro-optics phase-locked loop (EOPLL) LiDAR electro optical system frequency-modulated continuous wave (FMCW) LiDAR laser nonlinearity optical ranging |
| url | https://ieeexplore.ieee.org/document/9576527/ |
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