Broadband laser ranging (BLR) is essentially a spectral interferometer used to infer distance to a moving target. The light source is a mode-locked fiber laser, and chromatic dispersion maps the spectral interference pattern into the time domain, yielding chirped beat signals at the detector. A BLR record is a sequence of these chirped signals, representing consecutive target positions. To infer distance to a target, each underlying pulse envelope must be consistently registered and subtracted despite environmentally-induced variability. Then, nonlinear transformation of the phase is applied to remove the chirp, an FFT is performed to determine the peak frequency of the de-chirped signal, and a calibration factor relating de-chirped frequency to distance results in target position. Here, these analysis steps are discussed in detail.

Date Published: 22 February 2017
PDF: 11 pages
Proc. SPIE 10089, Real-time Measurements, Rogue Phenomena, and Single-Shot Applications II, 100890G (22 February 2017); doi: 10.1117/12.2255679

Published in SPIE Proceedings Vol. 10089:
Real-time Measurements, Rogue Phenomena, and Single-Shot Applications II
Bahram Jalali; Daniel R. Solli; Sergei K. Turitsyn; Günter Steinmeyer; Neil G. R. Broderick, Editor(s)