Long-wavelength transimpedance optical receiver performance enhancement using cooled germanium avalanche photodiodes

An optical sensitivity improvement of 1.5 dB was produced by moderate cooling of a commercially available 100 μm p+-n Ge APD in a transimpedance receiver, built on a standard printed circuit board. At 1.3 μm and 140 Mbaud, −45.2 dBm was achieved, making this receiver highly competitive where cooling is permitted.