High-precision brillouin scattering measuring system in ultrashort optical fiber

Abstract

The invention relates to a high-precision brillouin scattering measuring system in an ultrashort optical fiber. The system comprises a laser; an input terminal of an optical fiber coupler is connected with the laser at an output direction of the laser; an output terminal of the optical fiber coupler successively passes a first polarization controller, an optical fiber isolator, and a detection optical fiber and then is connected to one end of a circulator; the other output terminal of the optical fiber coupler successively passes a second polarization controller and then is connected to an input terminal of a single sideband modulator; an output terminal of the single sideband modulator passes an optical fiber amplifier and then is connected to the other input terminal of the circulator; an output terminal of the circulator passes a photoelectric detector and then is connected with a first input terminal of a lock-in amplifier; an output terminal of the lock-in amplifier is connected with a data collection processing system; and a square wave signal generator is respectively connected with a second input terminal of the single sideband modulator and a second input terminal of the lock-in amplifier. Meanwhile, according to the invention, a stimulated brillouin scattering gaining process and a stimulated brillouin scattering loss process are utilized, so that a detection sensitivity on a whole of a sensing optical fiber is improved and influences of interference signals like end surface reflection can be avoided; moreover, costs are reduced.

Description

technical field [0001] The invention relates to a high-precision measurement system for Brillouin scattering in an ultrashort optical fiber, in particular to a detection system based on stimulated Brillouin scattering. Background technique [0002] Stimulated Brillouin Scattering (Stimulated Brillouin Scattering) can be described as the nonlinear interaction of two beams of light in a medium (such as a silica fiber). When two beams facing each other (pump light with probe light ) meet in the fiber, and the frequency of the two beams satisfies the Brillouin frequency shift, energy exchange occurs. The process of stimulated Brillouin scattering is as figure 1 , two beams of optical pump light , probe light meet each other in the fiber, when the frequency minus When the frequency satisfies the Brillouin frequency shift, that is , due to the stimulated Brillouin scattering effect, energy transferred to , Light produces the gain of Brillouin scattering, i.e. ...

AI Technical Summary

Problems solved by technology

Traditional systems need to use at least 2 optical amplifiers and 2 electro-optical modulators, and can only detect a single stimulated Brillouin gain, which is easily affected by noise interference such as end-face reflections

Images