Bandwidth optimization of optical data links by use of error-control codes

A design approach to optimizing the bandwidth of optical data links while s imultaneously decreasing the bit-error rate is proposed. Mathematical analy sis indicates that bandwidth gains by factors of 10-60 with power gains of as much as 8.9 dB are possible. To achieve these performance levels require s several innovations. First, conventional forward error-correcting codes c annot be used because of their excessive hardware cost. A reasonably powerf ul multidimensional parity-based error-control code is proposed and analyze d. These codes offer excellent error detection and moderate error-correctio n capabilities. Most importantly, they can operate at the fast clock rates that are required. Second, a hybrid automatic repeat-request protocol is ex ploited to correct complex error patterns. In thermal-noise-limited systems this unique combination allows the optical clock rate to be increased sign ificantly, thereby resulting in large bandwidth increases. The proposed des ign approach can be used in optical data links in which propagation delays are moderate and is applicable to fibers that exploit wavelength-division m ultiplexing or time-division multiplexing, one-dimensional parallel-fiber r ibbons, and two-dimensional optical data links that use free space or guide d waves. Several design examples are illustrated. (C) 2000 Optical Society of America OCIS codes: 060.2360, 060.4510, 250.3140, 200.3760, 200.4650.