A stabilized fiber 3×3 coupler interferometric measurement system based on a first order feedback loop

In order to eliminate the influences resulting from environmental disturbances,a stabilized optical fiber interferometric measurement system configured with a fiber 3×3 coupler and fiber Bragg gratings(FBGs)was designed.By employing the FBGs as in-fiber reflective mirrors,both fiber Michelson interferometers in the system shared a commoninterferometric -optical path.One of the fiber interferometers was used to stabilize the system based on a first order electronic feedback loop for compensating for the environment jitter,while the other was used to perform the measurement task.The bandwidth of the feedback loop is 21Hz which endows the system stabilization for on-line precision measurement.