Optoelectronic reference X-band oscillator for radar systems

We present the design and results of studying the characteristics of an optoelectronic microwave oscillator in the freerunning regime are presented, propose a method for synchronising it with a signal of a highly stable crystal oscillator using a phaselocked loop, and analyse the results of an experimental study on the frequency instability of an optoelectronic microwave reference oscillator. The optoelectronic microwave reference oscillator with optical gain and a 10 GHz oscillation frequency simultaneously provides ultra-low phase noise (less than –142 dB Hz^-1) at a 10 kHz frequency offset from the microwave carrier and a low level of spurs in the oscillation spectrum (no more than –94 dBc). In this case, the temperature coefficient of the oscillation frequency is determined by the temperature instability of a highly stable crystal oscillator.