Optical Detectors and Receivers

Abstract

To implement an optical communication or sensing system one requires a means of extracting information contained in the modulation of an optical signal. It is possible to perform some all-optical functions on a received optical signal, such as optical amplification. It is also possible for a received optical signal to turn on another optical signal. Examples of all-optical signal processing will be discussed in Chapter 14. However, in the optical communication and sensing systems used today (and foreseen for some time to come) information is extracted from the optical signal by converting it to an electrical signal, and by then performing electrical signal-processing functions. The device which converts the optical signal into a voltage or current is called the optical detector. The electronic circuit which interfaces the detector (with its particular characteristics and requirements) to conventional electronic terminal equipment is called a preamplifier. The combination of the detector and the preamplifier is called a receiver.