DIFFERENTIAL MODE DELAY (DMD) FOR MULTIMODE FIBER TYPES AND ITS RELATIONSHIP TO MEASURED PERFORMANCE

With the introduction of Vertical Cavity Surface Emitting Lasers (VCSEL’s) used with multimode fiber (MMF), Differential Mode Delay (DMD), modal interference effects and the influence of connector interfaces are found to reduce the observed bandwidth of multimode fibers (MMF’s). In this study the performance of three example MMF’s is characterized by measuring DMD, effective modal bandwidth, and Bit Error Rate (BER) on the same three fibers. Fiber length is also considered. Controlling the spatial locations of the launch pulses, we develop methods aimed to certify the performance of optical fiber for 10Gb / s Ethernet. The source for these measurements was an 850 nm VCSEL.