fiber optic sensor system using a double -pass Mach-Zehnder interferometer

摘要

create a standard trigger signal of the correct 90-degree phase difference from the present invention, the physical basis of this variation an effective optical fiber sensor system using a double-pass Mach-Zehnder interferometer capable of demodulating starts. ; the optical fiber sensor system according to the present invention, a polarization controller, the first arm and mounted, to perform a phase modulation phase modulating portion made of a second arm mounted Mach-Zehnder interferometer; By a third optical fiber coupler sensor arm and the reference arm are connected for detecting the phase-modulated according to the physical changes, with a fiber coupler Michelson interferometer; An optical detector for extracting the interfering signal from the Mach-Zehnder interferometer and a Michelson interferometer by inducing the Fresnel reflection of the fiber coupler; And generating a trigger signal based on the zero cycle based on a signal detected by the optical detector, and using the reference trigger signal to trigger data acquisition of the second optical detector for extracting a physical change amount from the phase change of the two signals consists of computing units. Accordingly, the present invention as the trigger 90 generates a reference signal having a phase difference, non-linear or of the operating characteristics of the phase-modulated, it is possible to sample a precise 90 degree phase intervals, regardless of the form of the phase modulated signal.