A f-p interferometric optical fiber sensing system based on phase-generated carrier modulation

Abstract

The invention discloses an F-P interference optical fiber sensing system based on phase generation carrier modulation. First, an ASE light source emits spatial light, and the emitted spatial light is frequency-shifted by two acousto-optic frequency shifters AOM; after the frequency shift The two beams of light waves reach the focusing lens, and the two beams of light waves are focused and coupled into the optical fiber by the focusing lens, and propagate to the circulator through the optical fiber; the circulator contains three ports, and the light is transmitted by the first One port is input, and after the second port is output, it reaches the sensor probe containing the F-P cavity, and interference occurs in the light wave returned after passing through the F-P cavity, and the interference light carries a vibration or displacement signal, and the interference The light is then output from the third port of the circulator to the detector; the detector receives and detects and demodulates vibration or displacement signals. The above-mentioned system can realize interferometric measurement with high precision and large dynamic range, and meet the requirements of detection of large cavity length changes in practical engineering applications.

Description

An F-P Interferometric Fiber Sensing System Based on Phase-Generated Carrier Modulation technical field The present invention relates to optical fiber sensing technology field, relate in particular to a kind of F-P interference based on phase generation carrier modulation Fiber optic sensing system. Background technique At present, the interferometric optical fiber sensor is due to its compact structure, high sensitivity, anti-electromagnetic interference, remote monitoring, etc. Features have received extensive attention. It uses light waves as the carrier of signal transmission, and optical fiber as the medium of signal transmission and even sensing. When the external physical parameters, such as temperature, pressure, pressure, sound field, etc., change, the sensor will pass the sensor to the light wave in the fiber. The physical parameters are modulated, and the external physical parameters are obtained by collecting and analyzing the light waves whose physical ...

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Problems solved by technology

However, the premise of the three-wavelength phase demodulation method is to satisfy the quadrature phase condition. When the cavity length of the F-P cavity changes greatly, the initial quadrature phase condition will not be satisfied, and the data obtained by demodulation will be impossible. negligible error, which limits the effectiveness and engineering applicability of the three-wavelength phase demodulation method

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