Software Emulation Of Osnr For Dwdm System

With the increasing demands of network capacity, DWDM (Dense Wavelength Division Multiplex) technology has been widely used. OSNR (Optical Signal to Noise Radio) decides the quality of transmission and is a key parameter for DWDM system. How to test and verify multi-span DWDM system's OSNR is a difficult problem. One solution is to establish real network for testing, though the result is quite accurate, the cost is high, and duration long.For the questions mentioned above, based on long-year system design and deployment, this paper proposes a reliable OSNR software simulation solutiong for the multi-span DWDM system which can finish the OSNR verification in short time with the advantage of computer's high processing speed.Paper firstly analyzes the influence of each DWDM components on OSNR, especially the parameter of loss, dispertion, gain and noise; then, by establishing corresponding mathematical model for mux/demux, optical amplifier, fiber and dispersion compensation module, the simulation of OSNR is finaly realized at each reference point along the transmission direction (source signal-> mux-> amplifier 0-> dispersion compensation-> multi-span transmission-> demux). The simulation software is developed by Matlab language and its reliability is fully proved by comparision to the real-system testing results.By researching, OSNR simulation model for DWDM system is proposed, the corresponding algorithm and equation is verified. And with the use of this simulation software in some national DWDM backbone project, develop-cycle is shortened, efficiency got improved, and the outcome is quite satisfactory.