Laser Linewidth Requirements in Optical Binary Phase Shift Keying Communication Systems with Reed-Solomon Code

摘要

In this paper, effect of Reed-Solomon (R-S) code on the performance of optical binary phase shift keying (PSK) communication system has been analysed. Coding gain in terms of laser linewidth relaxation factor and reduction in the required optical power level has been determined. It has been observed that when R-S(31,27,2) code is used, coding gain in terms of laser linewidth relaxation factor for 1 GBPS system at a BER of 10~(-9) (required optical power -70.0 dBm at a laser linewidth of 3.7 MHz) is about 2.51, i. e. laser linewidth can be relaxed from 3.7 MHz to 9.3 MHz. When the coding gain is computed in terms of reduction in required optical power level for the above system, it is 8.3 dB, i. e. when the laser linewidth is 3.7 MHz, coded system will require a power level of -78.3 dBm instead of -70.0 dBm.