Self-mixing wavelength division multiplexing multi-channel displacement sensing system based on linear cavity multi-wavelength fiber laser

Abstract

The invention discloses a self-mixing wavelength division multiplexing multichannel displacement sensing system based on a linear cavity multi-wavelength fiber laser. The self-mixing wavelength division multiplexing multichannel displacement sensing system is characterized in that the linear cavity multi-wavelength fiber laser is used for generating multi-wavelength lasers and being matched with a multichannel dense wavelength division multiplexing unit to generate multipath light beams with independent wavelength lambda1, lambda2, lambda3 and the like to lambda n of each channel; a multichannel collecting and coupling unit emits multipath light beams, and the independent channels receive feedback optical signals from the scattering surfaces of detected objects in a one-to-one mode to form laser self-mixing signals; a photoelectric detector is utilized in a multichannel signal processing unit to receive multichannel self-mixing light signals with independent wavelengths and convert the multichannel self-mixing light signals to electric signals, and medium and post level circuits in the signal processing unit are used for processing the self-mixing signals. The self-mixing wavelength division multiplexing multichannel displacement sensing system is high in measurement accuracy, stable in working performance, wide in application range, and especially suitable for remote multichannel measurement.

Description

Technical field [0001] The invention relates to an optical interference displacement sensing technology, in particular to a self-mixing displacement sensing technology. Background technique [0002] Optical displacement sensing technology has the advantages of anti-electromagnetic interference, high sensitivity, large dynamic range, easy reuse, applicable to harsh environments such as high temperature and high pressure, inflammable and explosive, etc., and can fully solve the main problems of traditional electromechanical displacement sensors . The more common heterodyne interference displacement sensing technology in the interference displacement sensing technology includes a beam splitting unit and a converging unit, and the optical devices in each unit require precise collimation. Compared with traditional heterodyne interferometry technology, laser self-mixing technology has the characteristics of easy collimation, compact structure, and dexterity. At the same time, the sel...

AI Technical Summary

Problems solved by technology

The long cavity of the ring cavity fiber laser will reduce the sensitivity of displacement sensing and limit its application in long-distance displacement sensing

[0012] 3. The lower relaxation oscillation peak of ring cavity fiber laser seriously restricts the dynamic measurement range of laser self-mixing displacement sensing technology, causing many problems such as limited measurement bandwidth

The relaxation oscillation peak frequency of the ring cavity multi-wavelength laser varies between 20-140kHz affected by the pump power, which limits the bandwidth range of the post-processing circuit

When the displacement change frequency υ(t) is near the peak frequency of the over-relaxation oscillation, it will cause no response and limit the dynamic bandwidth

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