A Widely Tunable Narrow Linewidth RF Source Integrated in a Heterogeneous Photonic Module

Generating radio-frequency signals over the entire spectrum, from 1 to 100 GHz, typically requires the use of multiple oscillators designed only for specific narrow bands of operation within that spectrum. An optoelectronic system based on modulation side-band-injection-locked lasers is capable of generating RF frequencies tunable over a span of more than seven octaves with low phase noise . We present the results of our efforts to develop a heterogeneously integrated version of this system based on a silicon-photonic integrated circuit coupled to III-V semiconductor gain chips. Towards that end, we have successfully demonstrated an integrated laser module and achieved tunable RF generation with a ~ 1 Hz linewidth.