Directional Force Measurement Technology Based on Fiber-Optical Laser Heterodyning Demodulation

Distributed Bragg Reflector (DBR) polarimetric optical fiber laser sensors have been attracting great interests due to harsh environment capability and high signal-to-noise ratio. We demonstrate directional force measurement technology using dual-polarization DBR optical fiber laser as a sensor. The influences of external force (bending, current and ultrasonic signal) could be analyzed by inducing a DFB polarimetric laser sensor to detect the beating signals shifts when the cavity is perturbed. We present the analysis of sensing mechanism on the DBR geometric construction and demodulation of directional information by separating the dual orthogonal polarization modes. With loading angles at 35 degrees, 45 degrees, 55 degrees with 10 degrees interval, the DBR laser sensor has shown orientation recognization ability corresponding to beating signals shifts, offering a potential for vector force directional detection.