We present a laser Doppler velocimeter that stores and delays the reference beam to preserve coherence with a long-path-length measurement beam. Our storage and delay technique relaxes the strict coherence requirements associated with lidar laser sources, permitting the use of low-coherence lasers. This technique potentially could reduce the cost and size of lidar systems for commercial applications. Experiments that use fiber-optic ring resonators to store the reference beams and generate reference pulse trains validated the concept. We obtained results at several simulated distances by beating each usable reference pulse with a delayed Doppler-shifted measurement beam reflected off a rotating mirror.
© 2001 Optical Society of America
Adrian A. Dorrington, Rainer Kunnemeyer, and Paul M. Danehy, "Reference-Beam Storage for Long-Range Low-Coherence Pulsed Doppler Lidar," Appl. Opt. 40, 3076-3081 (2001)