Theoretical Analysis and Application of Absolute Distance Measurements Based on Electro-Optic Modulation and Optical Frequency Comb
【Abstract】To meet the requirements of high-precision, long-distance, and highly dynamic measurements, this article proposes a scheme for absolute distance measurement based on optical frequency combs. Cascaded phase modulators and intensity modulators are used to electro-optically generate a flat-top optical frequency comb. The system offers advantages, including direct traceability, cost efficiency, and reproducibility. Furthermore, a mathematical model is formulated and used to assess the quality of the optical frequency comb generated for use in a multi-heterodyne ranging system. The system is simpler than traditional multi-wavelength measurement systems, and realizes absolute distance measurements by extracting phase information from the synthesized wavelengths of the optical comb. The mathematical model presented herein is used to analyze the noise and uncertainty involved in the system.
【Keywords】 measurement; laser testing; optical metrology; photoelectric ranging;
(Translated by CAI ZJ)
 Zheng B F, Xie Q J, Shu C. Comb spacing multiplication enabled widely spaced flexible frequency comb generation [J]. Journal of Lightwave Technology, 2018, 36 (13): 2651–2659.
 Spencer D T, Drake T, Briles T C, et al. An opticalfrequency synthesizer using integrated photonics [J]. Nature, 2018, 557 (7703): 81–85.
 Zhao X, Li C, Li T, et al. Dead-band-free, highresolution microwave frequency measurement using a free-running triple-comb fiber laser [J]. IEEE Journal of Selected Topics in Quantum Electronics, 2018, 24 (3): 1–8.
 Wu H Z, Zhang F M, Liu T Y, et al. Absolute distance measurement by multi-heterodyne interferometry using a frequency comb and a cavity stabilized tunable laser [J]. Applied Optics, 2016, 55 (15): 4210–4218.
 Liu T Y, Zhang F M, Wu H Z, et al. Timefrequency analysis in absolute distance measurement using chirped pulse interferometry [J]. Chinese Journal of Lasers, 2016, 43 (9): 0904005 (in Chinese).
 Coillet A, Chembo Y K. Routes to spatiotemporal chaos in Kerr optical frequency combs [J]. Chaos: An Interdisciplinary Journal of Nonlinear Science, 2014, 24 (1): 013113.
 Sakamoto T, Chiba A. Multiple-frequency-spaced flat optical comb generation using a multiple-parallel phase modulator [J]. Optics Letters, 2017, 42 (21): 4462–4465.
 Mildner J, Meiners-Hagen K, Pollinger F. Dualfrequency comb generation with differing GHz repetition rates by parallel Fabry-Perot cavity filtering of a single broadband frequency comb source [J]. Measurement Science and Technology, 2016, 27 (7): 074011.
 Kuse N Y, Schibli T R, Fermann M E. Low noise electro-optic comb generation by fully stabilizing to a mode-locked fiber comb [J]. Optics Express, 2016, 24 (15): 16884–16893.
 Kourogi M, Nakagawa K, Ohtsu M. Wide-span optical frequency comb generator for accurate optical frequency difference measurement [J]. IEEE Journal of Quantum Electronics, 1993, 29 (10): 2693–2701.
 Wu R, Torres-Company V, Leaird D E, et al. Supercontinuum-based 10-GHz flat-topped optical frequency comb generation [J]. Optics Express, 2013, 21 (5): 6045–6052.
 Torres-Company V, Weiner A M. Optical frequency comb technology for ultra-broadband radio-frequency photonics [J]. Laser&Photonics Reviews, 2013, 8 (3): 368–393.
 Morohashi I, Sakamoto T, Sotobayashi H, et al. Broadband wavelength-tunable ultrashort pulse source using a Mach-Zehnder modulator and dispersion flattened dispersion-decreasing fiber [J]. Optics Letters, 2009, 34 (15): 2297–2299.
 Morohashi I, Sakamoto T, Sekine N, et al. Ultrashort optical pulse source using Mach-Zehnder modulator-based flat comb generator [J]. Nano Communication Networks, 2016, 10: 79–84.
 Kolner B H, Nazarathy M. Temporal imaging with a time lens [J]. Optics Letters, 1989, 14 (12): 630–632.
 Dou Y J, Zhang H M, Yao M Y. Ultra-short optical pulse generation based on optical frequency comb and application in optical analog-to-digital conversion [J]. Chinese Journal of Lasers, 2012, 39 (12): 1205006 (in Chinese).
 Yang T, Dong J J, Liao S S, et al. Comparison analysis of optical frequency comb generation with nonlinear effects in highly nonlinear fibers [J]. Optics Express, 2013, 21 (7): 8508–8520.
 Zhao X N, Qu X H, Zhang F M, et al. Absolute distance measurement by multi-heterodyne interferometry using an electro-optic triple comb [J]. Optics Letters, 2018, 43 (4): 807–810.
 Delfyett P, Bhooplapur S, Klee A, et al. Optical frequency combs from mode-locked diode lasersapplications in communications, signal processing & radar for avionics [C].∥2015IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) , November 10–12, Santa Barbara, CA, USA. New York: IEEE. 2015: 32–33.
 Yang R T, Pollinger F, Meiners-Hagen K, et al. Absolute distance measurement by dual-comb interferometry with multi-channel digital lock-in phase detection [J]. Measurement Science and Technology, 2015, 26 (8): 084001.