Patent ID: 11933646
Assignee: WUHAN UNIVERSITY OF TECHNOLOGY
Field: Measurement (Instruments)
Classification: CPC G  H  Y | IPC G  H

Claim 3:
4. The interferometric demodulation system for the large capacity fiber grating sensing network according to claim 1, wherein: the Mach-Zehnder interferometer comprises a 1×2 coupler and a 3×3 coupler, wherein: an input end of the 1×2 coupler is connected to an output end of the optical amplifier, a first output end of the 1×2 coupler is connected to a first input end of the 3×3 coupler, a second output end of the 1×2 coupler is connected to a third input end of the 3×3 coupler, a second input end of the 3×3 coupler is disabled, a first output end of the 3×3 coupler is connected to a first input end of the photoelectric converter, and a second output end of the 3×3 coupler is connected to a second input end of the photoelectric converter, a third output end of the 3×3 coupler is connected to a third input end of the photoelectric converter; and
the optical reflected signal returned by an each FBG in the grating array sensing network is divided into two channels through the 1×2 coupler, wherein: a hysteresis length of a channel of the optical reflected signal is N, the first input end of the 1×2 coupler to the 3×3 coupler is called a first interference arm, the second output end of the 1×2 coupler to the third input end of the 3×3 coupler is called a second interference arm, a sensing fiber length difference N between two interfering arms is not 0 and is less than a coherence length of a single FBG.