Development of system specification for laser-optimized 50-μm multimode fiber for multigigabit short-wavelength LANs

This paper presents the scientific arguments used in the specification development process by the Telecommunications Industry Association (TIA) Working Group FO-2.2.1 to develop the new multimode fiber and vertical-cavity surface-emitting laser specifications for high-speed application in data communications. Numerous engineering and commercial tradeoffs are described. The specification minimizes the link failure rate and overall link cost through utilization of communication-theory-based modeling and experimental verification. This was balanced against the reality of manufacturing costs attempting to maximize the yield of individual link components. The specific application used as an example has 50-μm graded-index multimode fiber operating at 10 Gb/s (e.g., 10 Gb/s Ethernet and fiber channel). The link performance is determined by the interaction of the fiber intermodal dispersion measured by the differential modal delay, and the transceiver launch distribution into the multimode fiber measured by encircled flux. A theoretically based model and the simulation approach that were used to simulate 40 000 links are described. The information from these simulations was used to determine the specification limits. In addition, sensitivity to the specification limits was evaluated. The experimental results of a round robin conducted by the TIA are presented, which confirm that the modeled performance would yield the expected results in actual practice.