Basic Operation of Optical Detectors

This short tutorial is a first introduction to optical detectors, which recover the signal from a fiber optic link. For RF/ microwave engi-neers, it may useful to think of this of optical detectors as the first bit of circuitry in a THz-frequency optical receiver. An optical front-end has a number of simi-larities to microwave circuitry. Both use low noise preamplifiers, filters and other signal processing, plus demodulators to recover data from the analog signal. The optical detector, however, is the component without an equiva-lent microwave counterpart, although it’s function is analogous to an antenna, extract-ing signals from the fiber as an antenna cap-tures a radiated signal.