PRECHIRP TECHNIQUE AS A LINEAR DISPERSION COMPENSATION FOR ULTRAHIGH-SPEED LONG-SPAN INTENSITY MODULATION DIRECTED DETECTION OPTICAL COMMUNICATION-SYSTEMS

Prechirp technique, as a linear dispersion compensation for intensity modulation direct detection (IM-DD) optical transmission systems, has been investigated theoretically and experimentally. This technique is based on a predistortion technique in an optical transmitter. Implementation to the ordinary IM-DD optical transmitter, which uses an external intensity modulator, is easily realized merely by adding a small injection current modulation to a semiconductor laser diode. Allowable optical transmission fiber dispersion will be more than doubled with this technique. Modified prechirp technique, which utilizes a time division superimposing prechirped bit streams, has also been investigated to achieve greater dispersion compensation capability.