Abstract

Because of their superior transmission characteristics, single-mode fibers (SMFs) are the transport medium of choice for future broadband-ISDN systems.¹ The use of SMFs with their nearly unlimited bandwidth reduces the likelihood of premature obsolescence of the installed fiber plant and enables the definition of BISDN interface rates and channel structures which are based on close-to-optimum coding rates for extended quality and high-definition TV. As a result, subscriber interface rates of ~150 and 600 Mb/s are being considered for standardization in the T1 Standards Committee in the United States and in CCITT Study Group XVIII. Transmission rates in the range of several Gb/s are expected to be employed in the trunk and loop-feeder network to support the future broadband services (Fig. 1). The recently introduced synchronous optical network (SONET) concept advocating a family of standardized optical interface rates is intended to simplify the multiplex process, create compatible transmission equipment, and provide midspan compatibility.²

© 1987 Optical Society of America