Abstract

The wavelength-division multiplexing (WDM) technique opens up new vistas in ultra high-capacity digital transport systems: the use of several optical channels tuned at different wavelengths and launched simultaneously into the same fiber enables one to achieve high aggregate bit rate [1, 2]. The total capacities reported in Refs. [1, 2] are well beyond the capacity allowed by single-channel systems. Wavelength multiplexing effectively lifts up the bit rate limit usually encountered in systems based upon a single carrier supporting the data stream. This limit is imposed by direct electronic modulation in semiconductor components or opto-electronic circuits and by the various distorsions experienced by short non-return-to-zero pulses through the fiber.

© 1995 Optical Society of America