Optimized ultra-high bit rate hybrid optical communication system design and simulation

Abstract

An optimized hybrid optical communication system for the bit rates of 160 Gbps, 100 Gbps and 40 Gbps is proposed. The system uses 1550 nm wavelength and consists of an optical fiber link for long-haul and a free space optical link for short-haul communication. For optical fiber link, the modified duo-binary return-to-zero modulation format with symmetrical dispersion compensation technique is used. For free space optical link, quadrature phase shift keying modulation technique with an atmospheric attenuation of 200 dB/km is considered. The system is also analyzed for the atmospheric fading effect of strong and weak turbulence. The performance of the proposed hybrid system is analyzed in terms of Q-value, bit error rate, eye opening, signal constellation diagram, etc. For a bit rate of 160 Gbps the optimized coverage distance obtained for the hybrid system is 419.93 km of fiber link and 129.34 m of free space link with strong atmospheric turbulence. To the best of author's knowledge such a high capacity and optimized hybrid system is proposed and analyzed for the first time. This system will be highly useful in optical networking and communication systems, where the front end will be a fiber link and back end will be a free space link or vice versa. � 2011 Elsevier GmbH. All rights reserved.