Discrete Raman Amplifier

Abstract

A discrete Raman amplifier comprises a Raman gain fiber, an input port into the Raman gain fiber for receiving optical signals to be Raman amplified, and an output port out of the Raman gain fiber for emitting Raman-amplified optical signals. A pump light input provides pump light to the Raman gain fiber at a plurality of wavelengths so as to provide Raman amplification over the selected signal wavelength range. Within both the pump light wavelength range and the selected signal wavelength range, the Raman gain fiber has only positive chromatic dispersion, and the Raman gain fiber has a moderate effective area.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to the field of fiber optical communications, and in particular to Raman amplification systems and techniques.[0003]2. Background Art[0004]Demand for large transmission capacity has been increasing exponentially due to the rapid spread of Internet services. There is thus an ongoing effort in the fiber optical communications industry to find cost-effective ways to meet this demand.[0005]Currently, network operators deploy optical fiber transport systems employing only one of either the C-band (1530-1565 nm) or L-band (1570-1610 nm). Erbium-doped fiber amplifier (EDFA) technology is typically employed to provide loss compensation. The transmission fiber typically used to implement these systems actually has a spectrum window that is wide enough to transmit signals over a wavelength range encompassing both the C-band and L-band (i.e., 1530-1610 nm), without a guard band (i.e., at 156...

AI Technical Summary

Benefits of technology

[0007]An aspect of the invention is directed to a discrete Raman amplifier comprising a Raman gain fiber, an input port into the Raman gain fiber for receiving optical signals to be Raman-amplified, and an output port out of the Raman gain fiber for emitting Raman-amplified optical signals. A pump light input provides pump light to the Raman gain fiber at a plurality of wavelengths so as to provide Raman amplification over the selected signal wavelength range. Within both the pump light wavelength range and the selected signal wavelength range, the Raman gain fiber has only positive chromatic dispersion, and the Raman gain fiber has a moderate effective area.

Problems solved by technology

A major obstacle, for deploying an optical transport system in C+L band is the lack of a wide-band optical amplifier that covers the wavelengths ranging from 1530 nm to 1610 nm, without any intermediate guard band (i.e., bandless).

However, conventional discrete Raman amplifiers (DRA) will degrade the performance of future WDM polarization-division-multiplexed (PDM) phase-modulated coherent systems.

In particular, conventional DRA designs fail to address a number of issues, including nonlinear impairments, associated system performance, and efficiency.

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