ABSTRACT
The design of an optical receiver depends on the modulation format used by the transmitter. Optical wireless receiver systems are very similar to fiber-based receiver systems. They consist essentially of a photodetector and a preamplifier, with possibly additional signal processing circuitry. This chapter discusses some of the key issues related to the specification and design of optical wireless receivers. The photodetector is an integral part of the optical front end of a wireless Infrared receiver because it converts an optical signal into an electrical signal. Four types of photodetectors are available for the design of optical receivers: avalanche photodiodes, photoconductors, metal-semiconductormetal photodiodes, and positive-intrinsic-negative photodiodes. Noise is an unwanted disturbance that masks, corrupts, and reduces the information content of the desired signal. Optical receivers and transmitters can have two types of integration: electronic and opto-electronic. Opto-electronic integration is under intense investigation by many laboratories around the world.
