Low noise tuned optical receivers using commercial 50 Omega modular microwave amplifiers

A noise-reduction technique for low-noise optical receivers using commercial 50 Omega modulator microwave amplifiers is presented. The technique is illustrated with the design of a receiver using a high impedance transmission line as an impedance-matching circuit between a PIN photodetector and a commercial 50 Omega modulator amplifier. A greater than 8 dB noise improvement relative to a 50 Omega untuned receiver over a 0.7 GHz bandwidth, and noise levels approaching those of high performance custom-mode receivers that employ packaged GaAs-FETs/HEMTs are reported.