Optical fiber hydrophone with quasi-reciprocity optical path

Abstract

The invention discloses an optical fiber hydrophone with a quasi-reciprocity optical path. Light emitted by a wide band light source is polarized into linearly polarized light by a shunt and a polarizer; two beams of orthorhombic light are formed by a 45-degree melting point; after being respectively modulated by a phase modulator, the two beams of orthorhombic light are rotated for 45 degrees by a delay optical fiber through a faraday rotator; then the two beams of orthorhombic light enter an acoustic probe by a polarization-maintaining coupler, enter a reciprocity compensated optical fiber by a 90-degree melting point by a polarization-maintaining optical fiber of the acoustic probe, and returns to the faraday rotator to be rotated by 45 degrees by the polarization-maintaining coupler; and finally, the two beams of polarized light in an orthorhombic mode are interfered at the position of the polarizer by the delay optical fiber. A photoelectric detector receives an interference optical signal containing sound pressure information and converts the sound pressure information into an electric signal to provide for a signal processing circuit; the signal processing circuit detects the electric signal to acquire a sound pressure signal serving as an output; and simultaneously, the output signal is applied to the phase modulator to implement phase modulation. According to a method disclosed by the invention, the polarization state random fluctuation in the optical path is inhibited and the phase signal caused by the sound pressure is effectively measured.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to an optical fiber hydrophone with a quasi-reciprocal optical path for detecting sound pressure by using interference light phase. Background technique [0002] Sound waves are currently the most effective carrier capable of transmitting information over long distances in the ocean. Detecting the space-time structure of the sound field formed by the sound wave carrying the signal in the ocean is an important means for underwater detection, identification, communication and environmental monitoring. It can be used for long-distance military target detection, seabed mineral development, fish schools Detection can also be used for telemetry of ocean dynamic processes (internal waves, circulation) and detection of ocean and land seismic waves. Therefore, advanced underwater acoustic detection technology is of great significance to national economy, national d...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the problems existing in the existing interferometric fiber optic hydrophones: the random fluctuation of the polarization state, or insensitivity to low-frequency signals, etc., the present invention proposes a fiber optic hydrophone with a quasi-reciprocal optical path

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