Ultrafast Photonic-to-microwave Transformer (PMT)

Ultrafast photodetectors with high quantum efficiency are required for optoelectronic generation of microwaves and millimeter-waves, ultra-high speed optical communication systems. Optical signals with subcarrier modulation at several hundred GHz can be achieved by using optical heterodyning techniques [1] or monolithic mode-locked diode lasers [2]. For example, sub-picosecond optical pulse generation at 350 GHz were demonstrated using a monolithic colliding pulse mode-locked quantum well laser [3][4]. These ultrafast optical pulses can be efficiently converted into millimeter-waves by broadband photonic-to-microwave transformers (PMT). This paper describes a broadband ultrafast PMT with nearly 100% efficiency at 100 GHz.