Photonics based RF comb generation up to 325 GHz

We demonstrate novel microwave photonic RF comb generators consisting of an ultra-low phase noise cutting edge fs-pulse laser and an InP-based high-speed photodetector subassemblies with rectangular RF waveguide interface. By combining the components, we generate broadband microwave comb spectra by optical-to-microwave downconversion with 1 GHz spacing in the D- and J-band. The single microwave tones obtain a high spectral purity with a measured spectral width below 1.5 Hz and high temporal stability. These properties can be exploited for test and measurement, wireless communication and RADAR applications.