Ultra-broadband and low phase noise photonic millimeter-wave generation

In this paper, we report on photonic millimeter-wave generation based upon optical heterodyning as well as external modulation for ultra-broadband and low phase noise operation. Using a special broadband high-power pin photodetector (PD) we demonstrate wideband (W-band) and broadband (DC-110 GHz) optical millimeter-wave generation. For wideband operation, we utilized a wavelength-tunable dual-laser setup. Here, the PD output was coupled to a rectangular WR10 waveguide output port and a subsequent limiting W-band amplifier. With this setup, we achieved wideband tunability within the W-band from 69 GHz to 112 GHz with a maximum output power variation below 3 dB and a saturated output power of 0 dBm. The 1dB compression point is about -4 dBm and the dynamic range is about 32 dB. For broadband operation, we have coupled the photodetector to a coaxial W1 output port allowing continuous frequency tunability from DC to 110 GHz with a maximum power penalty of only 6 dB and a maximum output power of -3 dBm. For generating low phase noise optical mm-wave signals, we have used an external modulator instead of the dual-laser. For an optically generated 100 GHz signal we have achieved a phase noise level of about -70 dBc/Hz at 10 kHz offset.