High-Speed Photodetectors: Applications in Telecommunication

This lecture discusses high-speed photodiodes and their applications in telecommunication systems. It begins with an overview of a digital optical communication system, highlighting the roles of laser diodes and multiplexing techniques. The instructor explains the importance of single mode fiber in transmitting optical signals and the use of avalanche photodiodes for signal detection. The lecture covers the different optical windows relevant to telecommunication, specifically at wavelengths of 0.8, 1.3, and 1.55 micrometers, emphasizing their significance in minimizing losses and achieving zero dispersion. The absorption spectra of various semiconductor materials, such as indium phosphide and indium gallium arsenide, are analyzed for their suitability in these applications. The instructor then introduces NMOS voltage amplifiers and discusses their polarization and coupling methods for high-frequency signals. The lecture concludes with practical examples of transimpedance circuits and the use of coaxial cables for signal transmission, ensuring minimal reflection and optimal performance in high-speed communication systems.