Transmission Limitations in Fibers due to Nonlinear Optical Effects

Abstract

The trend in long-haul lightwave communications is toward higher information capacity and longer repeaterless spans. The former entails high bit rates and wavelength multiplexing, while the latter requires maximum transmitter power and higher receiver sensitivity. In both cases, the ultimate limitations in lightwave transmission will be nonlinear optical interactions between the optical waves and the transmission medium, the optical fiber. These optical nonlinearities can lead to severe signal distortion and fading. Until recently, the whole area of optical nonlinearities in fibers was viewed by systems engineers as a curiosity that requires large solid-state or gas lasers to generate the nonlinear effects. However, a number of recent experiments have generated nonlinearities in silica fibers using injection lasers or lasers with outputs of only a few milliwatts. As lightwave systems become more sophisticated and injection laser powers increase to over 10mW, various optical nonlinearities will become important.