Improvements in speed, bandwidth, and phase noise of optically synthesized microwave oscillators

Using an optically injected semiconductor laser, we synthesize a wide range of microwave frequencies with tuning rates of 1 × 10
¹⁸
Hz sec over 10 GHz bandwidth. We show that opto-e1ectronic feedback narrows the linewidth of the microwave signal from 1 MHz to <; 10 Hz.