Automatic Power Control for a Frequency Tunable Optoelectronic Oscillator

Abstract

Automatic power control for a frequency tunable optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The OEO is implemented by a tunable microwave photonic filter using a phase-shifted fiber Bragg grating (PS-FBG) for frequency-tuning. Taking advantage of the automatic power control (APC), the problem of large power fluctuation in the OEO output signal during the frequency tuning or interfered by the external disturbance can be significantly improved and the functionality of equalization is realized. By adjusting the DC reference voltage of the automatic power control circuit, the tuning of RF signal power is conveniently achieved. To the best of the authors’ knowledge, this is the first time that the output power regulation of OEO has been implemented. For verification, the low-cost OEO at 2–7 GHz is established. Experiment results show that the output power fluctuation of less than 3 dB and a phase noise of −113 dBc/Hz@10 kHz are achieved.