Abstract

In long-haul optical amplifier transmission systems, high repeater output power is preferable to obtain the high optical signal-to-noise ratio (SNRo). However, the higher the repeater output becomes, the severer nonlinear^1–3 effects such as self-phase modulation, cross-phase modulation, and four-wave mixing due to fiber nonlinearity, affect the system performance. It is highly desirable to upgrade constructed single-carrier systems to wavelength-division-multiplexing (WDM) systems without reconfiguration of transmission line. This paper proposes a novel technique using nonlinear suppression lights (NSLs), which are located at different wavelengths from the transmitted signal in the transmission line. NSLs can equivalently adjust the signal power. We also experimentally confirmed the improved system performance through two-type systems.

© 1996 Optical Society of America