| Popis: |
Indium Phosphide (InP) avalanche photodiodes (APDs) are widely used in receivers for high-speed direct-detection lightwave communication systems. However, the material In 0.52 Al 0.48 As (referred hereafter as InAlAs) is considered as an avalanche material superior to InP due to lower excess noise factors in InAlAs than that in InP [1,2]. APDs using InAlAs avalanche region have thus been researched widely. To compare the performance of InP and InAlAs APDs in high-speed operations, we should evaluate the receiver sensitivity at a certain BER rigorously and with the inclusion of intersymbol-interference (ISI) in the analysis, instead of simply relying on a single APD performance parameter such as the commonly used excess noise factor, which is a measure of uncertainty in the avalanche gain (and it is due to the stochastic nature of the process of impact ionization). |
