Design of Bandwidth Adjustment Receiver for Optical Wireless Communication

Abstract

Infrared wireless communication possesses two main attractive advantages over its radio frequency counterpart, namely the abundance of unregulated spectrum in 700nm - 1500nm region and the ease with which the IR radiation can be confined. Integrating microwave electronics and optics, it is possible to provide wideband communication services but it is well known that the signal level in an optical wireless receiver is weakest at the front end. This paper presents the concerned with a systematic approach to the design of receiver for indoor optical wireless communication. In particular, it is concerned with how one properly chooses the front-end preamplifier and biasing circuitry for the photodetector; and comparison of technique using bandwidth adjustment for better service quality with a bootstrapped transimpedance amplifier is presented. A controllable capacitance is introduced at the output of the second stage of the amplifier. This technique permits a bandwidth adjustment from 52Hz to 233MHz for a capacitance range of 10uF to 1pF.