Abstract

All-optical regeneration will be of key importance for future large-scale and high bitrate optical networks. Several techniques for all-optical 2R and 3R regeneration have been recently investigated.^1–4 Although 3R regenerators are generally preferred for application in high bitrate systems, 2R regenerators may be of use at lower bitrates. Moreover, 3R regeneration can be based on the combination of a 2R regenerator (also called optical decision circuit) and a clock extraction system. The quality of an optical 2R regenerator can a.o. be defined by its ability of noise reduction and extinction ratio improvement, two factors that can be derived from the optical decision characteristic. The decision characteristics of the optical regenerators proposed recently, such as SOA-based interferometric wavelength converters,^1,2 and SOA-based Mach-Zehnder or Michel-son interferometers,³ were not truly digital in the sense that the slope of the regeneration characteristic was rather slow. Here we experimentally demonstrate for the first time a quasi-ideal optical decision characteristic with a very sharp transition between the two digital states. The 2R re-generator used in the experiment is based on a Mach-Zehnder interferometer (MZI) with gain-clamped SOA’s (GCSOAs) in both arms. The principle of this regenerator has been presented earlier by the authors.⁵ Here we demonstrate that quasi-ideal optical decision characteristics with adjustable threshold can be obtained experimentally using this regenerator structure.

© 2002 Optical Society of America