High Performance Optical Oscillators for Microwave and mm-wave Applications

Optical oscillators are evolving rapidly, and a new and compelling approach for improving the performance of advanced data, communications, radar and other systems that require high performance oscillators with small size, weight and power, at frequencies in the range of 10 to 300 GHz. The most widely known photonic oscillator is the opto-electronic oscillator (OEO). The OEO is based on a feedback loop that converts modulated light from a laser to RF (microwave/mm-wave) frequency. OEO is a versatile architecture that allows for the interchange of components in the optical loop with their electronic counterparts, or vice versa. A new type of miniature optical resonator has been employed for use in the OEO. Known as whispering gallery mode (WGM) resonators, these are structures made with a transparent material and are geometrically axio-symmetric, ranging in size from a few mm to a few tens of microns in diameter.