Optoelectronic phase tracking and electrooptic sampling of free-running microwave signals up to 20 GHz in a laser-diode-based system

Reports optoelectronic phase-tracking and electrooptic sampling of microwave signals from a free-running oscillator in a laser-diode-based system. A voltage-controlled oscillator (VCO) in a photoconductive harmonic mixer based phase-lock loop is utilized to gain switch a 0.8 μm laser diode for phase-tracking of the microwave signal at frequencies up to 20 GHz. The phase and amplitude of the microwave signal in a microstrip line is also measured using another 1.3-μm laser diode driven by the VCO.