Optimization and application of broadband fiber Raman amplifiers

Abstract

Fiber Raman amplifier (FRA) was first demonstrated by Stolen and Ippen in the early 1970's. From the mid- to late- 1990s, with technological advance in some important fields, such as new types of fiber with high Raman gain coefficient, new Raman pump lasers with high output power and some all fiber components, there has been revived interest in distributed Raman amplifier (DRA). Since then, DRA has been studied extensively due to its fundamental advantages compared with the lumped amplifier, such as Erbium doped fiber amplifier (EDFA). First, Raman gain can be obtained in all kinds of fiber and hence it is easier to upgrade the existing transmission line from the terminal ends. DRA can also improve the noise performance and reduce the penalty from fiber nonlinear effects in transmission system, allowing for longer amplifier spans, higher bit rates and smaller channel spacing. In addition, since stimulated Raman scattering (SRS) is a non-resonant effect, Raman gain is available over the entire low attenuation region of optical fiber ranging from approximately 1.3/zw to 1.6///W.