Interference type optical fiber vibration sensing demodulation system and method based on photoelectric oscillator

Abstract

The invention provides an interference type optical fiber vibration sensing demodulation system and method based on a photoelectric oscillator, and the system mainly comprises a light source, an electro-optic modulator, an interference type vibration sensing unit, a polarization controller, a polarizer, a photodetector, a microwave amplifier, a power divider and a frequency monitoring unit. In theinvention, the electro-optic modulator is used to generate phase-dependent polarization orthogonal carrier waves of different frequency components and a first-order single-sideband, polarization characteristics are adopted to separate the carrier waves and first-order single-sideband such that the carrier waves and first-order single-sideband are transmitted along two interference arms in the interference type vibration sensing unit, and the phase difference containing the vibration signal to be measured is converted into a change in the microwave oscillation frequency of the photoelectric oscillator with a high Q value. Therefore, the vibration signal to be measured can be demodulated by monitoring the frequency change of the microwave signal output by the photoelectric oscillator. Thisamount of frequency change is proportional to the vibration signal to be measured, and the proportionality factor is determined by the frequency of the optical carrier, so that vibration detection anddemodulation with high sensitivity, high accuracy and fast response can be achieved.

Description

technical field [0001] The invention relates to the technical fields of optical fiber optics, optical fiber sensing, optical fiber hydrophones, microwave photons, etc., and in particular to an interference type optical fiber vibration sensing demodulation system and method based on a photoelectric oscillator. Background technique [0002] Vibration is an important topic in many fields of modern physics and science and technology. Vibration sensing is widely used in hydrophones, seismic monitoring, oil wells, security, and condition monitoring of construction projects and infrastructure. Compared with traditional electromagnetic vibration sensors, fiber optic vibration sensors have the characteristics of anti-electromagnetic interference, corrosion resistance, small size, easy reuse and easy networking, and have attracted the attention and research of relevant scholars. According to the different physical parameters to be modulated, fiber optic vibration sensors can be divide...

AI Technical Summary

Problems solved by technology

However, the output optical power of the interferometer has a sinusoidal relationship with the vibration signal to be measured, which greatly limits the dynamic range of the vibration sensor

At present, phase-generated carrier (PGC) technology is often used to improve the performance of fiber optic vibration sensors, but this requires an external microwave signal source and the demodulation algorithm used limits the performance of the system to a certain extent

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