Fiber-optic laser Doppler velocimeter using an external-cavity semiconductor laser

Abstract
Influence of the spectral linewidth Δν of a semiconductor laser on the performance of a fiber-optic laser Doppler velocimeter (FLDV) was investigated. By using an external-cavity laser with Δν≂0.3 MHz, we could build a FLDV having an optical fiber probe length up to 25 m long.