Modeling of multimode fiber systems

Abstract

The optical communication is of great interest in developing extensive, highspeed networking infrastructures. Optical fibers provide many advantages over traditional copper cables and wireless links. Among these advantages are high security, low electromagnetic interference, extremely low loss, very high ban dwidths, and highly manageable cabling. However, the very small wavelengths associated with optical radiation require very small waveguide dimensions. Waveguide dimension of single mode fiber (SMF) are < 10um, resulting in relatively poor yield in device manufacturing. For most of the last-mile networks topologies, cost constraints limit the appeal of SMF. Large core fibers allow for less restrictive manufacturing tolerances; however, they also results in multi mode propagation that exhibit distortion from the dispersion in propagation among the many modes. The distortion can be prohibitively large for data rates approaching and exceeding i Gb/s.// Improvement of the de ployability of these multi mode fibers depends on the proper design of the multi mode fiber link parameters for the reduction of the over estimation. Conventional multi mode fiber model ignores all the effects of the different laser mode profiles in the link simulation and over estimates the penalty. Proposed modified model for vertical cavity surface emitting laser (VCSEL) based mult imode fiber (MMF) links considers all effects of different laser mode profiles and compare the transmitted eye diagrams and Q- Factors with the conventional model.// Significant differences observed in the eye diagrams and the Q- factors of the modified model compared to the conventional model with various kinds of graded index mult imode fibers and VCSEL. 29 % of Q- factor improvement observed in laser optimized MMF link with rate of 10 Gb/s and distance of 300 m.