An all-fiber laser Doppler velocimetry system based on an acousto-optic zero coupler

Abstract

The invention discloses an all-fiber laser Doppler velocity measurement system based on an acousto-optic zero coupler. The system includes: lasers, isolators, acousto-optic zero couplers, self-focusing lenses, adjustable attenuators, Bragg gratings, piezoelectric ceramics, and photodetectors. Wherein, the laser is a fiber laser, the isolator is a fiber isolator, the acousto-optic null coupler is a fiber null coupler, and the Bragg grating is a fiber Bragg grating. This system realizes the separation of signal light and reference light, the frequency shift of light wave, and the combination of signal light and reference light by adopting acousto-optic frequency shifting zero coupler. With one acousto-optic zero coupler, the functions of two couplers, one circulator, and one acousto-optic frequency shifter in the traditional optical path are realized, the structure is simplified, and the cost is effectively reduced. In addition, the acousto-optic zero coupler and fiber Bragg grating used in this system are commercial single-mode fibers, which are truly all-fiber structures, and their insertion loss is very small, thus further reducing the optical path loss.

Description

technical field [0001] The invention relates to the technical field of photoelectric detection, in particular to an all-fiber laser Doppler velocity measuring system based on an acousto-optic zero coupler. Background technique [0002] Laser Doppler velocimetry (LDV) has been widely used and developed rapidly due to its advantages of high velocity measurement accuracy, wide velocity measurement range, high spatial resolution, fast dynamic response, and non-contact measurement. The optical fiber can be used to send the detection beam and transmit the scattered light in a long distance or in a harsh environment, which greatly simplifies the collimation system of space light and is easy to realize distributed measurement. Therefore, the all-fiber Doppler velocimeter is a kind of Application prospect of speed sensor. [0003] figure 1 It is a typical all-fiber laser Doppler velocimetry system. like figure 1 As shown, a typical all-fiber laser Doppler velocimetry system inclu...

AI Technical Summary

Problems solved by technology

[0006] The present invention aims to provide an all-fiber laser Doppler velocimetry system based on an acousto-optic zero coupler to overcome the above-mentioned problems or at least partially solve the above-mentioned problems, so as to solve the complex structure of the existing all-fiber Doppler vibrometer system. , large insertion loss and high cost

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