Self-Oscillation Multicarrier Light Source Based on Recirculating Frequency Shift Loop

A novel scheme of self-oscillation multicarrier light source based on recirculating frequency shift loop (RFSL) is proposed and experimentally demonstrated in this paper. Compared with conventional RFSL-based multicarrier generation schemes, the radio frequency (RF) signal for driving the modulator in RFSL is generated by an internal self-oscillation of the optical carrier instead of the external commercial RF source device. The self-oscillation method significantly reduces the cost of the light source and decreases the phase noise of RF signal and multicarrier signal. In the experiment, we successfully generate a single-mode oscillation RF signal with the phase noise of −85.10 dBc/Hz at 10 kHz offset frequency. A total of 49 multicarrier optical signals from 1550.59 nm to 1554.44 nm with the power fluctuation as low as 3 dB are obtained. The frequency interval is approximately 10.014 GHz, which is equal to the oscillation frequency of the RF signal.