Doppler velocity measuring system based on monolithic integration double frequency laser device

Abstract

The invention discloses a Doppler velocity measuring system based on a monolithic integration double frequency laser device. The Doppler velocity measuring system comprises the monolithic integrationdouble frequency laser device, a beam splitter, an optical fiber circulator, an optical transmitting and receiving antenna, an erbium-doped optical fiber amplifier, a beam combiner, a photoelectric detector, a low-pass filter and a signal collection and processing module. The monolithic integration double frequency laser device is taken as a light source, and the system is small in volume, low inpower consumption and high in reliability; a signal extraction part consists of the single photoelectric detector and one low-pass filter, the requirement on the bandwidth of the photoelectric detector is low, and the system is simple in structure and easy to realize.

Description

technical field [0001] The invention discloses a Doppler velocity measurement system based on a single-chip integrated dual-frequency laser, and relates to the technical field of laser measurement. Background technique [0002] Laser Doppler velocimetry technology is a technology that uses the Doppler effect of lasers to measure the speed of objects, because it has the advantages of high spatial resolution, fast response speed, high measurement accuracy, and no need for contact measurement. Huge development and wide application. [0003] Laser Doppler speed measurement technology is divided into two types: single-frequency speed measurement and dual-frequency speed measurement. The single-frequency laser Doppler velocity measurement system uses a single-frequency laser as the light source. The single-frequency laser Doppler velocity measurement system has the problem of DC drift, poor anti-interference ability, and is easily affected by environmental disturbances, which gre...

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Problems solved by technology

[0004] In the prior art, a tunable, coherently locked dual-frequency laser source can be used to measure the velocity as low as 26μm / s in the range of short distance and long distance. The sensitivity of the measurement method is improved compared with the traditional method, but its dual-frequency laser source uses two separate single-mode distributed feedback semiconductor lasers, which is bulky, complex in structure, and difficult to maintain; its signal extraction part uses two photodetectors , one photodetector is used to generate the beat frequency signal of the two lasers, and the other photodetector is used to generate the beat frequency signal of the two lasers after Doppler frequency shift, which requires a higher bandwidth of the photodetector; The Doppler frequency shift of the moving object can only be obtained by mixing the two beat frequency signals by the frequency converter. The mixer requires high signal power, which will affect the speed measurement effect of the entire system; Instrument bandwidth requirements are high

[0005] To sum up, the existing dual-frequency laser speed measurement device has the disadvantages of bulky, complex structure, high hardware requirements, difficult maintenance, and difficult application

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