High Performance, Miniature, Wideband Signal Generator for mm-Waves

OEwaves has pioneered the use of photonics for generation of spectrally pure RF signals. The micro Opto-Electronic Oscillator (MOEO) provides the highest reported spectral purity at Ka-band in a package the size of a postage stamp. This technology, based on OEwaves crystalline whispering gallery mode (WGM) resonator, can be modified to provide wideband tunability, together with its high spectral purity and small SWaP. In the proposed program, OEwaves will utilize the difference in frequency response of modes of different families in a WGM resonator made with electro-optic material to realize wideband tunability. Tunability is achieved by application of a DC voltage on the resonator, which will result in different frequency shifts of transverse electric (TE) and transverse magnetic (TM) modes of the resonator. Two lasers injection locked to each mode will also move in frequency in response to the applied DC field, and their beat on a fast photodetector produces the desired tunable MMW signal. This approach directly addresses the requirements for a widely tunable, high performance and low SWaP signal generator. It also naturally lends itself to the extension of the frequency of operation to the ultimately desired value of 300 GHz. Since the electro-optic effect is extremely fast, the architecture provides sub microsecond agility, limited only to the settling time of the resonator.