Optoelectronic microwave oscillator

TLDR

The study introduces a novel oscillator that converts continuous light energy into stable, spectrally pure microwave signals. The oscillator employs a pump laser, intensity modulator, optical fiber delay, photodetector, amplifier, and filter, and a quasi‑linear theory predicts threshold, amplitude, frequency, linewidth, and spectral density, with experimental data validating the model. The device generates ultrastable, spectrally pure microwave reference signals up to 75 GHz with phase noise below –140 dBc/Hz at 10 kHz.

Abstract

We describe a novel oscillator that converts continuous light energy into stable and spectrally pure microwave signals. This optoelectronic microwave oscillator consists of a pump laser and a feedback circuit including an intensity modulator, an optical fiber delay line, a photodetector, an amplifier, and a filter. We develop a quasi-linear theory and obtain expressions for the threshold condition, the amplitude, the frequency, the line width, and the spectral power density of the oscillation. We also present experimental data to compare with the theoretical results. Our findings indicate that the optoelectronic microwave oscillator can generate ultrastable, spectrally pure microwave reference signals up to 75 GHz with a phase noise lower than -140 dBc/Hz at 10 kHz.