Optical fiber interferometer sensor disturbance signal demodulation device based on single sideband frequency modulation

Abstract

The invention discloses an optical fiber interferometer sensor disturbance signal demodulation device based on single sideband frequency modulation. The optical fiber interferometer sensor disturbancesignal demodulation device based on the single sideband frequency modulation comprises a laser, a modulator, a frequency modulation source, an optical filter, an optical amplifier, an optical isolator, a Michelson interferometer, a PZT, a photodetector and a data sampling card. The optical fiber interferometer sensor disturbance signal demodulation device based on the single sideband frequency modulation disclosed by the invention introduces a microwave frequency modulation source and uses a frequency sweeping method, so as to avoid high requirements of the traditional internal modulation PGCmethod for a direct modulation laser source and reduce a relative intensity noise; and the invention adopts a 12-point quadrature demodulation algorithm to avoid additional electrical noise caused bythe use of an electric mixer, therefore, the measurement dynamic range is large and fully automatic measurement can be realized, the demodulation algorithm is simplified, and the cost is reduced; meanwhile, the system disclosed by the invention can effectively detect array sensors of any distribution, so that the applicability of the system is stronger.

Description

technical field [0001] The invention belongs to the technical field of optical communication, and in particular relates to a demodulation device for a disturbance signal of an optical fiber interferometer sensor based on single sideband frequency modulation. Background technique [0002] Optical fiber hydrophones are widely used in earthquake prediction, oil exploration, safety detection, etc., because of its high sensitivity, large dynamic range and immunity from electromagnetic interference. Generally speaking, the fiber optic interferometer sensor unequal arm system can be divided into Michelson and Mach-Zehnder structures, and the demodulation of the disturbance signal on the signal arm uses the phase-generated carrier (PGC) technology. The principle of traditional internal modulation PGC technology is to use an unbalanced interferometer to introduce a large-amplitude phase modulation signal of a certain frequency outside the bandwidth of the detection signal into the in...

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Problems solved by technology

The structure of the device is simple, but due to the reference source part on the reference arm of the "wet end" of the optical fiber interferometer, the "wet end" has not been fully optical fiberized, and it is difficult to realize the construction of a large hydrophone array

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