Fiber-optic laser Doppler velocimeter with non-mechanical scanning of spatially encoded points for cross-sectional velocity distribution measurement

摘要

A fiber-optic laser Doppler velocimeter (LDV) combining non-mechanical scanning and multipoint measurement is proposed for two-dimensional velocity distribution measurement on a cross-sectional plane. The LDV consists of a main body including a tunable laser and LiNbO_3 phase-shifter array, and a probe including diffraction gratings. The phase-shifter array is used to generate spatially encoded measurement points aligned in the transverse direction by multichannel optical serrodyne modulation, and these points are axially scanned with wavelength change. Two-dimensional velocity-distribution measurement is demonstrated using a probe setup with an 8-channel beam array.