A Widely Tunable Narrow Linewidth RF Source Utilizing an Integrated Heterogeneous Photonic Module

Generating RF signals over the entire spectrum, from hundreds of MHz to the hundreds of GHz, typically requires the use of multiple oscillators which operate only for specific bands within that spectrum. By mixing two lasers together, it is possible to generate RF signals over that entire band. Through the use of a narrow linewidth low frequency oscillator, optical modulator, and injection locking, much higher frequency outputs can be produced that still retain the narrow linewidth of the low frequency oscillator. Here we present the results of our efforts to develop an integrated version of this system based on a silicon-photonic integrated circuit coupled to III-V semiconductor gain chips. Towards that effort, we have successfully demonstrated an integrated module and shown tunable RF generation with a 1 Hz linewidth.