Estimation of multiple-quantum well laser parameters for simulation of dispersion supported transmission systems at 20 Gbit/s

In this paper, a set of multiple-quantum well (MQW) laser parameters is proposed for simulation of optical transmission systems at 20 Gbit/s. The parameters have been estimated by joint fitting of a small signal intensity modulation (IM) response model to five measured IM response curves of a strained layer MQW laser, using the Levenberg-Marquardt method. Good agreement between theoretical and experimental curves was obtained. Using these laser parameters, we have assessed the performance of dispersion supported transmission systems at 20 Gbit/s incorporating an erbium doped fibre amplifier (EDFA) or a semiconductor optical amplifier (SOA) as a booster amplifier. It is shown that the use of a SOA, with an unsaturated gain of 20 dB, improves the system performance for link lengths ranging from 8 to 20 km of standard single mode fibre (SMF) due to partial chirp compensation in the SOA, and degrades the system performance between 1.2 and 2.5 dB for link lengths ranging from 30 to 50 km. The increase of the unsaturated gain of the SOA from 20 to 25 dB is only advantageous for link lengths ranging from 8 to about 12.5 km where a small performance improvement, less than or equal to 0.8 dB, is observed. The influence on the system performance of an increase of the laser line width enhancement factor from 2 to 3 is also investigated