All-optical fiber type self-mixing distance measuring system of laser

Abstract

The invention discloses an all-optical fiber type self-mixing distance measuring system of laser, which is characterized in that a tunable laser and an output end of a coupled system send a laser signal with an initial wavelength of lambada, a tuning frequency of nu m, and a tuning range of delta lambada to a to-be-measured object through light collection, and receives a feedback signal comes from a scattering face of the to-be-measured object to form a self-mixing signal of the laser; an optoelectronic signal conversion unit receives the self-mixing signal of the laser and switches the self-mixing signal of the laser to an electrical signal; a signal processing unit utilizes the vibration frequency delta nu L of the self-mixing signal of the laser to obtain the distance between the scattering face of the to-be-measured object and an output end of the tunable laser. The system has high measuring accuracy, stable performance, and wide application occasions, and is particularly suitable for distant measurement.

Description

technical field [0001] The invention relates to an optical detection system for the absolute distance of a target object, in particular to a self-mixing laser ranging system. Background technique [0002] The optical detection of the absolute distance of the target can be widely used in mining, electric power, water conservancy, communication, environment, construction, agriculture, forestry and many other fields. In the prior art, the time-of-flight ranging method based on pulsed laser has relatively low precision and low sensitivity; the heterodyne phase laser rangefinder system includes a reference arm and a measuring arm, and the structure is relatively complicated; tuning based on injection current The semiconductor laser self-mixing ranging technology has the advantages of compact structure, light weight, small size, high reliability, suitable for on-site measurement, etc., and has gradually been widely used. [0003] The principle of laser self-mixing distance measur...

AI Technical Summary

Problems solved by technology

[0018] 1. Since the amplitude of the injection current of the semiconductor laser is limited by the working range of the injection current of the semiconductor, thus limiting the tuning range of its output wavelength, the tuning range of a typical current injection type F-P semiconductor laser is generally around 10nm

According to the principle of ranging, the tuning range Δλ is small, resulting in a decrease in measurement accuracy, and it is impossible to achieve high-precision ranging;

[0019] 2. When the current injection type semiconductor laser is tuned, the working performance of the laser is unstable, and the output power fluctuates seriously, resulting in unstable output self-mixing signal and affecting the ranging effect;

[0020] 3. The typical linewidth range of semiconductor lasers is 2nm, and they generally work in multiple longitudinal modes, resulting in poor monochromaticity and coherence of the laser beam, which affects its transmission and sensing characteristics, and the divergence angle is large when working at a long distance, which directly limits Application occasions and working distance of laser self-mixing ranging technology

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