A Microwave Optoelectronic PLL Synthesizer Based on Optical Comb Reference

Abstract

A tunable high-resolution synthesizer based on optoelectronic phase locked loop is proposed for the generation of microwave and mmWave frequencies. Optical modulation, frequency division, and phase locking processes are deployed to generate a tunable lower frequency exhibiting suppressed phase noise. Moreover, a dense tunable optical comb locked to the widely spaced reference is produced. A suite of microwave and mmWave frequencies in multiple frequency bands emerges from the beating of the generated optical frequency components and optical or electrical filtering may isolate the frequency bands of interest. The phase noise of the synthesized frequencies depends on the optical power of the input reference comb. The experimental evaluation, including Allan deviation and phase noise measurements, prove the high stability performance of the proposed scheme.