Laser phase noise measurement based on modified self-homodyne optical coherent receiver with a Faraday rotating mirror

A novel laser phase noise measurement method based on self-homodyne structure with a Faraday rotating mirror (FRM) and an optical coherent receiver is proposed and experimentally demonstrated. The proposed method is simple in structure and easy to operate. Compared with the ordinary phase noise measurement system of self-homodyne optical coherent receiver, the length of the required delay fiber is halved and the polarization of the optical signal is more stable. Experimental results show that the proposed method can accurately characterize the phase noise and the linewidth of the laser under test, which are consistent with those obtained by the conventional self-homodyne method.