The Study On Multi-mechanism And Multi-parameter Distributed Sensing

Distributed Optical-fiber Sensor (DOFS) has the advantages of electromagnetic interference resistance, corrosion resistance and electrical insulation just like optical fiber sensor, also can get on a path along the fiber optical measurement field in time and space distribution of continuous information. Distributed Optical-fiber Sensor's sensing mechanism including: based on scattering technology, based on light interference technology, based on optical fiber Bragg grating (FBG) prospective distributed technology, based on the polarized OTDR technology, etc. And the technology based on scattering also including:based on Rayleigh scattering, based on Raman's effect, based on Brillouin's effect, etc. In these sensing mechanism Brillouin DOFS can realize the temperature and stain measurement, Raman DOFS only can realize the temperature measurement, FBG can realize the temperature and stain prospective distributed measurement, light interference DOFS can realize the vibrate of outside measurement.This paper will combine these different sensing mechanisms to realize multi-parameter measurement. Because of Brillouin DOFS exits the cross sensitivity problem, can't realize the temperature and stain measurement at the same time. So we proposed and realized dual-parameter sensing technology based on dual-optical-fiber, and because of BOTDA and Mach-Zenhder interferometer distributed optical-fiber sensor are using the loop sensing fiber structure, so we proposed combine BOTDA and Mach-Zenhder interferomete together with Sharing the same sensing optical fiber, light source, and other optical devices to realize the temperature (or stain) and vibrate measurement. Then, because of Brillouin scattering is sensitive to temperature and strain, but Raman scattering is only sensitive to temperature, so we can combine Brillouin scattering and Raman scattering together to realize Dual-Parameter measurement. At last, combine Brillouin DOFS and FBG optical-fiber sensor together can realize the point and distributed multi-parameter measurement.