Noise performance of an InP/InGaAs superlattice avalanche photodiode

The noise performance of an InP/InGaAs Superlattice Avalanche Photodiode (S L-APD) has been studied theoretically to examine its suitability as a detec tor in optical receiver units. The results indicate that the device which h as a very large gain-bandwidth product (approximate to 450 GHz) provides a high receiver sensitivity compared to conventional APD. The device also exh ibits a very low value of excess noise factor which results in a high value of signal-to-noise ratio. The SL-APD is expected to find useful applicatio ns as a high sensitivity photodetector in long-haul fibre optic communicati on systems. For a digital system, the device exhibits a very low value of b it-error rate (BER) even at moderate gain.