Synthetic optical frequency-stepped chirp signal and its high resolution ranging demonstration

Synthesizing wideband optical frequency-stepped chirp signal (FSCS) with independent lasers for high resolution ranging is suggested. Based on the theory of FSCS signal ranging, both the influence of laser parameters on synthesizing FSCS signal and their error tolerances are investigated. Numerical results show that among the three laser parameters, jitters in starting frequency and starting time are the main factors causing range resolution deterioration. Meanwhile, a high resolution ranging experiment with optical FSCS signal is demonstrated, where the FSCS signal is simulated by optical chopping a linear wavelength sweeping laser at the center wavelength of 1550 nm and line width of 150 kHz. Both the theoretical analysis and the experimental results show that it is workable to form synthetic FSCS signal with several linear-chirped lasers for high resolution ranging.