Noise Properties and Time Response of Superlattice and Conventional Avalanche Photodiodes

点击翻译按钮获取中文摘要

In a lightwave communications system imparting information on a lightbeam and transmitting it, for instance through a fiber, is one aspect. A second and equally important aspect is the extraction of the information at the receiving end. This must be done so as to have little distortion in the reproduction of the original information. Of importance in doing this is increasing the strength of (amplifying) the received signal after it has been converted from light back to an electrical signal. Otherwise the overall signal strength would be too feeble to complete with random electrical signals (noise) contributed from the overall receiving process. A second approach would be to amplify the incoming optical signal rather than the converted electrical signal, however, for the moment at least it appears more favorable to amplify electrically. The reason is two-fold: inherent noise added in the amplification process, and the amplification magnitude that can be produced. On both accounts, electrical amplification is superior up to the present. The present proposal deals with the important aspects of electrical amplification of optical information with a minimum of accompanying noise. New artificially taylored electronic materials promise to provide better performance than more conventional natural materials. Understanding the noise generation, the materials design, and amplification processes are crucial and are the central topics of the present effort.