Applied Physics Seminar

The use and manipulation of optical fields allows one to address challenging problems that have traditionally been approached with microwave electronics.  Some examples that benefit from the low transmission loss, agile modulation and large bandwidths accessible with coherent optical systems include signal distribution, coherent communications and arbitrary waveform generation.  We have recently extended these advantages to demonstrate a microwave generator based on a high-quality factor (Q) optical resonator and a frequency comb functioning as an optical-to-microwave divider.   We call this approach optical frequency division (OFD), and it provides a 10 GHz electrical signal with absolute phase noise below -100 dBc/Hz at 1 Hz offset, and a corresponding fractional frequency instability ≤8x10-16 at 1 s.  When integrated from 1 Hz to 5 GHz, the timing jitter of such a 10 GHz signal is only a few femtoseconds.  By this metric, our photonic microwave generator is 100x more stable than the best electronic microwave oscillators.  Beyond a description of the architecture and properties of the photonic microwave generator, I will also discuss fundamental limitations to this approach as well as initial efforts aimed at implementing the OFD technique in a micro-resonator platform.