Photodetectors

Photodetectors are an integral part of photonics systems. Since photodetectors are critical for the receivers by converting light into electrical signals, the performance requirements are usually very stringent. In ber optical telecommunication systems, photodetectors are typically made from III-V semiconductor materials because of the superior noise and bandwidth performance of these discrete devices. Due to the indirect band-gap and transparency in the near infrared, silicon has played an insignicant role in telecom applications. When the silicon platform was being considered for high performance, low cost photonics circuits, monolithically integrated photodetectors were very important for the success of these systems. Since Si initially was only considered for applications in the visible, Ge became the semiconductor material of choice because of its excellent absorption properties in the near-infrared and the seamless monolithic integration into CMOS processes.