InGaAs/InAlAs Avalanche Photodiode With Low Dark Current for High-Speed Operation.

Waveguide InGaAs/InAlAs avalanche photodiodes (APDs) with high bandwidths (>40 GHz) and low dark current (<50 nA at 90% of breakdown voltage) were demonstrated. The excess noise is low, corresponding to $k ~ \sim ~ 0.2$ line in the local excess noise model. Using these values bit error rate (BER) was calculated to assess the potential of our APDs. Calculated sensitivities of −21.5 dBm at 25 Gb/s and −14.2 dBm at 40 Gb/s are predicted for a BER of 10^{-10} . Analysis showed that with lower amplifier noise, the low dark current and low excess noise from our APDs are necessary to optimize the sensitivity. [ABSTRACT FROM PUBLISHER]