A Distributed Optical Fiber Sensing Device Based on Brillouin Fiber Laser

Abstract

A distributed optical fiber sensing device based on a Brillouin fiber laser, including a narrow linewidth pump laser, an erbium-doped fiber amplifier, a pulse signal generator, a polarization scrambler, an optical isolator, etc., using the Brillouin fiber laser The dual output ports output two beams of light waves with a frequency difference of about one Brillouin frequency shift. One beam of frequency-tunable Brillouin laser is pulse-modulated as pump light, and the other beam is used as continuous probe light. The adjustable Brillouin laser output is realized by the temperature controller of the Brillouin laser cavity. The frequency-tunable pulsed pump light and the continuous probe light undergo Brillouin interaction in the sensing fiber. The signal processing at the back end of the sensing system is the same as that of the general Brillouin optical time domain analysis system. The pump and probe light are provided by the Brillouin fiber laser, which can save the adjustable microwave source and supporting modulator in the general Brillouin optical time domain analysis system, greatly reducing the cost and complexity of the entire system. Facilitate system optical integration and packaging.

Description

technical field [0001] The invention belongs to the technical field of Brillouin fiber laser and distributed fiber optic sensing, and in particular relates to a distributed fiber optic sensing device and method based on Brillouin scattering. Background technique [0002] Due to its unique characteristics, the Brillouin fiber laser based on the Brillouin scattering effect, the Brillouin Stokes light generated by stimulated Brillouin scattering, its frequency is shifted down by one compared to the Brillouin pump light. Brillouin frequency shift, its value depends on the material and doping characteristics of the fiber itself on the one hand, and is also affected by environmental factors such as ambient temperature and strain on the other hand. In addition, the Brillouin scattering laser line width is narrow, and the laser structure is simple. The application research of Brillouin fiber laser has become a research hotspot, and it has been used in vibration sensors, optically g...

AI Technical Summary

Problems solved by technology

At present, the commonly used method to obtain two beams of oppositely transmitted pump light and probe light is to use electro-optical modulation microwave source for frequency shifting. This method requires an expensive high-performance adjustable microwave source, and high-speed modulators are often difficult to work stably.

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