OPTICAL COMMUNICATION SYSTEM, PARTICULARLY IN THE SUBCRIBER AREA

摘要

There are disclosed a method and apparatus for producing laser pulses at two wavelengths alternately by switching the oscillations of a distributed feedback semiconductor laser of the continuous grating type back and forth across the stop band. The necessary shaping of the gain or index of refraction characteristic along the path of the oscillations is accomplished in part by two top electrodes, one of which is longer than the other along that path, and by varying the current supplied to at least one of those electrodes in the appropriate sense. Applications for optical communication and for optical logic are disclosed, the preferred embodiment being a transmitter for an optical communication system with minimal chirp of the optical pulses, in which pulses at one of the wavelengths are modulated at a bit rate exceeding 1 Gigabit by direct-modulationcontrol of the switching of the laser, and the pulses at the other of the two wavelengths are discarded.