Radio frequency (RF) and microwave signals are integral carriers of information for technology that enriches our everyday life – cellular communication, automotive radar sensors, and GPS navigation, among others. At the heart of each system is a single-frequency RF or microwave source, the stability and spectral purity of which is critical. While these sources are designed to generate a signal at a precise frequency, in practice, the exact frequency is blurred by phase noise arising from component imperfections and environmental sensitivity that compromises ultimate system-level performance.
This reality drives undesirable tradeoffs between performance, environmental sensitivity, and size that make the simultaneous achievement of stability, precision, and agility in an ultra-compact form factor an elusive feat. However, DARPA’s Generating Radio Frequency with Photonic Oscillators for Low Noise (GRYPHON) program could change all of that, as performers recently demonstrated in the first phase of the program aimed at developing compact, ultra-low-noise microwave frequency oscillators.