High Resolution Dynamic Strain Sensor using a Polarization Maintaining Fiber Bragg Grating

Dynamic strain sensing based on fiber Bragg gratings (FBG) has found a wide range of applications in structure health monitoring and industrial process control. Conventional approaches to enhance strain resolution upon the standard configuration have shown challenges in scaling up due to much-increased system complexity. In this report, we demonstrate a new scheme based on an FBG sensor fabricated in a polarization-maintaining fiber. By using balanced detection to suppress laser intensity noise and enhance strain signal, we have demonstrated an improvement of 28 dB in signal level, 18 dB in signal-to-noise ratio, and 20× in strain resolution when compared to the results using a regular FBG sensor. Moreover, this new sensing concept does not require complicated frequency locking systems and hence allows easy scaleup.