850 nm Germanium Photodetector Performance

Photodetectors made from silicon-germanium have been pursued for the past two decades as a way to bring near infrared detection capability into a low-cost silicon process. The raw performance of Ge on Si detectors at 850 nm has been found to be close to that of GaAs devices in optical properties, and the leakage current for these relatively large devices is nearing that needed for many applications. Further receiver data shows that the Ge detectors are comparable to commercial receivers based on GaAs detectors at 4 Gb/s with a sensitivity lower than -18 dBm and jitter performance less than 40 ps