Laser self-mixing interference measuring system

Abstract

The invention discloses a laser self-mixing interference measuring system, which comprises a laser, a coupler, a measurement channel, a reflector and a photoelectric detector, wherein the coupler has a first port, a second port and a third port; the first port of the coupler is connected with the output end of the laser; the measurement channel is connected with the second port of the coupler and is used for detecting a measured object; the reflector is arranged at the third port of the coupler and is used for controlling the feedback light; and the photoelectric detector is used for detecting the output power of the laser. According to the laser self-mixing interference measuring system, active control of the feedback light is realized through the reflector, so that control of waveform of the output power of the laser can be realized, measurement requirement is reached, measurement precision can be improved favorably, and measurement range is enlarged. The measuring system, with the advantages of a laser self-mixing interferometer and optical fiber transmission being combined, is simple in structure, small in size, capable of realizing miniaturized sensing detection and wide in application range.

Description

technical field [0001] The invention relates to the technical field of laser measurement, in particular to a laser self-mixing interference measurement system. Background technique [0002] There is a common but extremely important phenomenon in the application of laser systems - optical feedback. The so-called optical feedback phenomenon refers to the phenomenon that after the laser output light is reflected or scattered by external objects, part of the light is fed back to the laser resonator. Optical feedback will seriously affect the output characteristics of lasers. Therefore, for the application system using lasers as light sources, researchers initially focused on how to eliminate the adverse effects of optical noise, spectral line broadening, and coherent quenching caused by optical feedback. With the deepening of the research, the researchers found that the feedback light carried the information of the external object, so they began to actively study how to use the...

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Problems solved by technology

[0004] However, the measurement method based on laser self-mixing interference is highly dependent on the reflectivity of the measured object. If the reflectivity of the object is low, the measurement cannot be realized; if the displacement direction of the object is to be determined, the interference fringes must be able to form a sawtooth wave. The object under test is required to have a sufficient level of optical feedback

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