Phase noise suppression method and device for remote optical fiber interference system with spectral line operation

Abstract

The invention relates to an optical fiber sensing technology and provides a method and device for phase noise suppression of a remote optical fiber interference system in spectral line operation. The device comprises a narrow linewidth single frequency laser, a first electro-optic phase modulator, an erbium-doped optical fiber amplifier, a transmission optical fiber, a second electro-optic phase modulator, an optical fiber Michelson interferometer, a photoelectric detector and a signal collecting and processing device. The method comprises the steps of applying modulating signals at the input end of the transmission optical fiber through the electro-optic phase modulators to generate multifrequency laser, utilizing the modulating signals of the electro-optic phase modulators again at the output end of the transmission optical fiber to recover the multifrequency laser generated by modulation to single frequency laser, simultaneously enabling phase difference between the two modulating signals to be odd number times of pi, and enabling the two modulating signals to have identical frequency and amplitude. The two electro-optic phase modulators are utilized to achieve recoverable spectral line operation, an SBS is suppressed, system phase noises are reduced, and accordingly maximum input power and the sensing distance of a sensing system are improved.

Description

technical field [0001] The invention relates to optical fiber sensing technology, in particular to a remote optical fiber interference system based on recoverable spectral line operation and a phase noise suppression method thereof. Background technique [0002] Interferometric optical fiber sensing technology has been widely used in underwater acoustic signal detection, oil exploration, seismic wave detection and other fields due to its high sensitivity, large dynamic range, and anti-electromagnetic interference. With the further development of technology, in recent years, interferometric optical fiber sensing technology is developing towards large array and long distance. However, the increase in the distance of the transmission fiber leads to the occurrence of various nonlinear effects. In particular, stimulated Brillouin scattering (SBS) has become the most prone nonlinear effect in long-distance transmission systems due to its low-threshold characteristics. When the s...

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Problems solved by technology

[0006] The present invention aims at the problem that the maximum input power of the system caused by SBS is low, the phase noise is large, and the phase noise increases due to laser broadening caused by phase modulation in the existing remote optical fiber interference system, and a remote interference optical fiber based on recoverable spectral line operation is proposed. Phase noise suppression method and device for sensing system

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