Optical-fiber laser for fixed-point scanning based on wavelength feedback

Abstract

The invention relates to an optical-fiber laser for fixed-point scanning based on wavelength feedback. The optical-fiber laser comprises a scanning light source, a second directional coupler, a band-pass filter and a wavelength feedback loop; the band-pass filter is connected between an output end of the scanning light source and the second directional coupler; the wavelength feedback loop comprises a photoelectric transformer, an electrical level judging module and a scan-range controlling module; the photoelectric transformer, the electrical level judging module and the scan-range controlling module are connected in sequence; an input end of the photoelectric transformer is connected with an output end of the second directional coupler; and an output end of the scan-range controlling module is connected with the scanning light source. Therefore, the scan-range can be controlled by judging wavelengths through the band-pass filter; wavelength fixed-point scanning and controlled precise point-to-point scanning can be realized by the wavelength feedback loop; system resource required on sampling and processing is saved greatly; and sampling frequency and sampling accuracy are greatly increased. Besides, the optical-fiber laser for fixed-point scanning based on wavelength feedback is simple in structure, low in cost and wide in application range.

Description

technical field [0001] The present invention relates to the technical field of optoelectronics, in particular to the technical field of fiber lasers, in particular to a fixed-point scanning fiber laser based on wavelength feedback. Background technique [0002] Optical fiber sensing system based on FBG (Fiber Bragg Grating) technology is the most widely used technology in optical fiber sensing, widely used in the stress health monitoring of bridges, tunnels, dams and other buildings, as well as the temperature of petroleum and transmission and transformation cables monitoring and other industries. Its basic principle structure generally adopts the following two technical solutions: figure 1 The broadband light source plus direct spectral analysis scheme shown and as figure 2 The scanning light source plus time-domain analysis (indirect spectral analysis) scheme. [0003] Solution 1 is characterized by simple technology, but due to the high cost of the spectrometer for sp...

AI Technical Summary

Problems solved by technology

like image 3 As shown, when sampling, in order to ensure the stability of the system under the influence of temperature, humidity, life, etc., more than half of the sampling points are useless (only one useful FSR is needed in the system each time), these useless use Points will occupy system resources, and in the case of the same system resources, the sampling frequency will be more than doubled, or the sampling accuracy will be reduced by more than half

This has a serious negative impact on key performance indicators such as scanning frequency and accuracy of the entire FBG demodulator

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