OPTICAL EQUALIZATION TO COMBAT THE EFFECTS OF LASER CHIRP AND FIBER DISPERSION

In a high-speed long-haui fiber-optic communication system using direct modulation and direct detection, fiber chromatic dispersion can cause serious performance degradations, particularly in the presence of laser chirp. Optical equalizers for countering the fiber dispersion and improving performance are described here. They consist of both reflective and transmissive cavity structures. The equalizers are adaptive in the sense that the positions of their periodic frequency responses are optimally adjusted in real time. The equalizers are evaluated by using computer simulation routines based on the rate equations for intensity-modulated lasers. It is shown that, by using equalizers of the type proposed, the receiver data eyes remain open well beyond where they would close without equalization. © 1990 IEEE