Distributed Acoustic Sensor Using Broadband Weak FBG Array for Large Temperature Tolerance

We demonstrate distributed acoustic sensor using broadband weak fiber Bragg grating array for large temperature tolerance in an φ-optical time domain reflectometry system with a balanced Michelson interferometer. The system was tested with large difference in local temperature, 18 °C and 50 °C, simultaneously, and achieves a relatively flat frequency response from 20 Hz to 1200 Hz.