CHAPTER 2

TELECOMMUNICATIONS, CABLE TELEVISION, AND DATA-LINK SYSTEMS

Paul W. Shumate

BACKGROUND

At all the Japanese sites it visited, the JTEC Optoelectronics Panel observed a determined commitment to developing multimedia services and their enabling optoelectronics technologies. The Japanese see multimedia as the most strategic factor for moving into the 21st century, in terms of benefiting the Japanese population and in terms of remaining competitive in international markets. Large and small Japanese businesses are building research, development, and marketing programs around multimedia concepts like NTT's VIP (Visual, Intelligent, and Personal) paradigm for emerging telecommunications services and NEC's C&C (Computers and Communications) vision. The enabling technologies for these kinds of visions include high-speed digital communications, switching, high-capacity information storage, image processing, high-definition and flat-panel displays, new kinds of consumer electronics, and local networks. Optoelectronics plays a major role in nearly all of these, with the possible exception of image processing.

This study specifically does not deal with displays or most consumer electronics; instead it focuses on high-speed optical transmission (10 Gbit/s and beyond), data links to beyond 1 Gbit/s, and on asynchronous-transfer-mode (ATM) switching (to a lesser degree). High-speed digital transmission and switching for telecommunications have been major thrusts for companies like Fujitsu, Hitachi, and NEC for nearly two decades. Due largely to the influence of Nippon Telephone and Telegraph (NTT), Japanese telecommunications products have always been at the leading edge. Japanese transmission equipment pioneered in the use of single-mode fiber, high bit rates, and long wavelengths, and NTT was early to commit to the Asynchronous Transfer Mode (ATM) standard for multiplexing and switching. NTT's vision for bringing multimedia telecommunications services to private residences has always been fiber-to-the-home (FTTH). Only recently, due to other countries' attention to analog coaxial-cable (particularly in the United States) and wireless technologies, has the Japanese government's Ministry of Posts and Telecommunications (MPT) expanded the nation's vision to include other alternatives. NTT has responded by revising its fiber-to-the-home timetable from reaching every home by 2010 to being available to every home from a nearby termination by that year - that is, by terminating fiber close to groups of homes and provisioning on an as-needed (or willing-to-pay) basis (New York Times 10 January 1995, D-2). Meanwhile, at least two large consortia are planned (see the cable TV section of this chapter) that will introduce cable television service into Japan on an accelerated schedule using hybrid fiber/coaxial-cable networks (Wall Street Journal 9 February 1995, B-4). Undoubtedly these new networks will be well positioned to play an important role in distribution of multimedia and broadband services. To facilitate the growth of cable TV, MPT is deregulating that industry.

In Japan, the development of telecommunications transmission systems has been strongly influenced by the visions and timetables of NTT and, to a growing degree, by international market opportunities. Key aspects of NTT's commitments are those to multi-Gbit/s backbone trunking networks throughout Japan, to fiber-to-the-home, and to ubiquitous single-mode fiber. Current plans for the backbone network are for 10 Gbit/s, with a view toward much higher rates in the future. Some suppliers are already working to equal the historical trend of 4-fold capacity (and/or speed) improvement per product generation with R&D efforts on 40-Gbit/s systems and research on 160 Gbit/s systems. In response to NTT's plans for fiber-to-the-home, many vendors are developing novel low-cost lasers for digital transmission, as well as linear lasers and optical amplifiers for analog subcarrier video.

Overseas sales are of growing importance to Japan's optoelectronics industry. For a decade and a half, traditional suppliers of transmission equipment (e.g., Fujitsu and NEC) have been designing systems for export to the United States based on modifications to domestic products. But three major developments have increased the focus on designing new transmission equipment specifically for export. The first development is the worldwide standardization of Synchronous Digital Hierarchy (SDH) (called Sonet in the United States) for transmission, and the standardization of ATM for multiplexing and switching. The second development is the recent move, especially in the United States, from trials to deployment of residential broadband access networks such as fiber-to-the-curb (FTTC), hybrid fiber/coax (HFC), and fiber-to-the-home (FTTH). The third development is the growing market worldwide for cable television service and the associated fiber-based distribution systems.


Published: February 1996; WTEC Hyper-Librarian