Excited Brillouin scattering gain spectrum measuring method and system thereof

Abstract

The invention discloses an excited Brillouin scattering gain spectrum measuring method which comprises the steps of (1) conducting beam splitting on a beam of continuous laser generated by a laser device to obtain two beams of lasers, using one beam of laser as pumping light to be injected into a medium to be measured, enabling the excited Brillouin scattering effect to be generated in the medium to be measured, generating Stokes light which is opposite to the injected pumping light in transmission direction, using the other beam of laser as a light carrier to be modulated through an electrooptical modulator with loaded periodic electrical signals, and obtaining reference light, and (2) simultaneously inputting the reference light and the stokes light in a photoelectric detector, obtaining the light current through heterodyne detection, and using an electron spectrometer to process the light current to obtain an excited Brillouin scattering gain spectrum. By means of the excited Brillouin scattering gain spectrum measuring method, the bandwidth requirements of using equipment such as the modulator, the detector and the electron spectrometer can be reduced, and measurement on characteristics such as line types and the bandwidth of the excited Brillouin scattering gain spectrum is easily and stably achieved.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to a method for measuring a stimulated Brillouin scattering gain spectrum and a system thereof. Background technique [0002] Stimulated Brillouin Scattering (SBS, Stimulated Brillouin Scattering) is a common nonlinear effect, which is a light scattering phenomenon caused by the interaction between the pump light incident on the medium and the elastic acoustic wave in the medium. The scattering process consumes the pump light and produces acoustic waves and Stokes light whose frequency is shifted down relative to the pump light, and the distribution of the Stokes light can be characterized by the SBS gain spectrum. The SBS gain spectrum has extremely narrow bandwidth and is widely used in the fields of fiber optic sensing, fiber optic communication, microwave photonics and so on. In fibers with different structures and different lengths, the SBS gain spectrum bandwidth ...

AI Technical Summary

Problems solved by technology

Since the resolution of existing conventional spectrometers is only on the order of 1 GHz, which is much larger than the gain spectrum bandwidth of SBS, it is impossible to directly measure the accurate SBS gain spectrum line shape and bandwidth information from the spectrum

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