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This paper describes the first implementation of optical fiber technology for the I/O channel connections of the IBM Enterprise Systems Connection (ESCON™) Architecture™. The ESCON optical link line rate is 200 megabits per second and is capable of transmission over distances of 3 km. The link is composed of a serializer, electro-optic transmitter, duplex fiber optic cable, electro-optic receiver, and deserializer. The serializer and deserializer respectively perform the conversions from parallel to serial and serial to parallel formats. The clock which is used to retime the serial data in the deserializer is extracted from the encoded serial signal using a phase-locked loop (PLL) technique. The optical link technology selected to achieve the data processing system requirements is InGaAsP/InP 1300-nm LED, InGaAsP/InP PIN photodiode, and multimode optical fiber. A duplex fiber jumper cable is designed with a rugged, low-profile, polarized connector, with a unique protective cap which recedes as it is mated. The optical link loss budget is determined by dividing the link into two major categories: available optical power and cable plant loss. The link design ensures that the minimum available power is greater than the maximum cable plant loss. The design parameters and trade-offs of the optical link are discussed in this paper. Unique measurement techniques and tools to ensure reliable and consistent link performance are described.
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