System and method for ranging with dual-sweeping light sources based on cascaded interferometers

Abstract

The present invention relates to a dual-sweep frequency light source ranging system and method based on a cascade interferometer, wherein the coherent light emitted by the first frequency sweep light source and the second frequency sweep light source enters an optical fiber coupler, and enters the main interferometer after being split. And the cascaded Mach-Zehnder interferometer, the coherent light entering the main interferometer is first split by the fiber coupler, and part of it enters the common path interferometer containing the sample through the fiber circulator, and the returned sample interferes with the spectral signal and the fiber coupler The output from the other end enters the balance detection device of the interference spectrum signal together to form an interference spectrum signal, which is collected synchronously with the reference interference signal formed in the cascaded Mach-Zehnder interferometer. The light emitted by the second frequency-sweeping light source enters the fiber coupler, and another part of the light after splitting enters the light source frequency detection unit, and the wavelength signals are collected synchronously. The invention can improve the accuracy and reliability of measurement.

Description

technical field [0001] The invention relates to the technical field of absolute distance measurement, in particular to a cascaded interferometer-based dual-sweep light source ranging system and method. Background technique [0002] With the development of high-end manufacturing, aerospace manufacturing, automobile manufacturing and unmanned driving and other fields, distance measurement is a particularly important aspect. Among the absolute distance dynamic measurement systems and methods currently used, the frequency-sweeping interferometry method has the advantages of large measurement range and high measurement accuracy. In order to improve the measurement accuracy of frequency-sweeping interferometry, many universities and research institutions at home and abroad have researched and reported on this method. Chinese Patent Publication No. CN106226775 A, application publication date December 14, 2016, titled "A Dynamic Absolute Distance Measuring System Based on Sweeping ...

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Problems solved by technology

However, in this method, there are many photoelectric devices, complex structures, large devices, and high cost. The reference interferometer is easily affected by the external environment, which introduces measurement errors, and the system has requirements for the linearity of the frequency-sweeping light source.

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