Modern Optical Communications is a fascinating marriage of the disciplines of physics, optics and communication technology. Although the transmission of information by optical means had been practiced in rudimentary form for centuries prior to the advent of the laser, it was with the invention of that device that serious efforts got underway to exploit the potential advantages of information carriers located in the optical portion of the electromagnetic spectrum. Much of the impetus for these efforts has been provided by the explosive growth of information handling requirements generated by both the military and civilian markets, and the resultant search for ever-greater channel capacity. In this regard, the potential of a single optical channel to provide a capacity in excess of 1012 bits/second is indeed attractive. Other, less dramatic, advantages of optical links that have been cited are privacy or security, decreased susceptibility to electromagnetic inter-ference, relatively low power consumption, compactness, and comparatively low cost.