Frequency-Tunable OEO Using a DFB Laser at Period-One Oscillations With Optoelectronic Feedback

A simple frequency-tunable optoelectronic oscillator based on a distributed-feedback (DFB) laser under optical feedback at period-one (P1) oscillation is proposed and experimentally demonstrated. The directly modulated DFB laser functions as an active tunable microwave photonic filter and a high-efficiency modulator due to the high-efficiency response at the P1 oscillation frequency, eliminating the needs of the narrowband electrical bandpass filter and high-gain RF amplifier. By tuning the optical feedback ratio, tunable microwaves ranging from 8.6 to 15.2 GHz with single sideband phase noise below -110.88 dBc/Hz at a 10-kHz offset from the carrier were realized.