In this paper, the influences of the relative intensity noise (RIN), in particular the relaxation oscillation noise, of an erbium distributed feedback (DFB) fibre laser has been investigated theoretically and experimentally for use a polarimetric ultrasonic sensor. We show that the relaxation oscillation noise and the ultrasonic signal both induce modulation sidebands on the polarization beat frequency of the DFB laser ultrasonic sensor. We present a novel demodulation algorithm for the polarimetric DFB fibre laser ultrasonic sensor, which can effectively eliminate the influences of the intensity noise and slowly varying drift of the polarization beat frequency.
|Number of pages||9|
|Journal||Journal of Lightwave Technology|
|Publication status||Accepted/In press - 13 Jun 2019|
- ultrasonic sensor
- fibre laser
- intensity noise