N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 5 - SONET, WDM, DWDM and B-ISDN Technologies                                                             Slide 15 of 76 _________________                                                                                  __________

                                                        Light Detectors

                                         Convert Signals Acceptable to the End-Terminals 

                                         Photodiodes

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The Light detectors at the receiving end of the optical transmission detect a light beam, amplify it, and convert it back into electrical signals. Photodiodes are used to detect and amplify light. Positive-intrinsic-negative (PIN) photodiodes and Avalanche photodiodes (APD) are the most widely deployed photodiodes. APDs are similar devices to PIN photodiodes, but provide gain through amplification.