In-Fiber Auxiliary Interferometer to Compensate Laser Nonlinear Tuning in Simplified OFDR

The traditional optical frequency domain reflectometry usually requires a separate auxiliary interferometer to compensate for laser nonlinear tuning effect. In order to break through this limitation, this paper proposes a simplified optical frequency domain reflectometry system by integrating an in-fiber auxiliary interferometer before the sensing fiber. We experimentally characterized the laser nonlinear tuning effect, and then verified the feasibility of the proposed system in compensating the laser nonlinear tuning effect by both simulation and experiment. Finally, the capabilities of the distributed sensing of our proposed system was confirmed by the temperature and strain sensing experiments.