Abstract

Attainable transmission distance of ultra-high speed transmission systems is restricted by both transmission loss and chromatic dispersion of the fiber. The advent of practical optical amplifiers drastically relaxed the former limitation. The remaining problem is how to overcome the latter limitation. Precisely controlled dispersion shifted fibers (DSF) for ultra-long distance NRZ transmission or soliton transmission are very effective approaches for high speed transmission systems. However, huge amounts of single-mode fiber cables have been already installed to create real networks. The key issue is a way to enhance the existing fiber cables (including DSFs) for higher-speed or longer transmission applications. Therefore, transmission systems with dispersion compensation have been proposed and demonstrated using a IF-band delay equalizer, dispersion compensation fiber, and a phase conjugator, respectively [1-4]. Recently, a compact and passive optical delay equalizer with large specified dispersion was realized using planar lightwave circuit (PLC) technology [5,6]. As this equalizer is based on a Mach-Zehnder (MZ) interferometer, the desirable dispersion characteristics appear in the optical frequency domain periodically. In this paper, from the view point of cost-effectiveness and multi-channel upgradability, we propose a transmitter combined with a PLC delay equalizer, and successfully demonstrate penalty free dual 10 Gbit/s transmission over 132 km standard fiber.

© 1994 Optical Society of America