Optical Transmission Using Ultra-long Raman Fibre Laser Amplification: in Optical Communication Systems

As technology progresses, demand for information has become more immediate, driven by the Internet. The exponential increase of data traffic over the past decades facilitated the development of technologies capable of delivering higher capacities. However, the current design of optical networks based on lumped amplification method (EDFA) accounting for more than 90% of all commercially deployed amplifiers will not be able to accommodate less-noise resistant high level modulation formats to handle the capacity requirements in a single mode optical fibre. Low noise distributed Raman amplification is a promising alternative that can overcome the limits set by EDFA and satisfy the bandwidth demand. The unique amplification method that uses fibre Bragg grating to form an ultra-long Raman fibre laser minimises the variation of the effective gain-loss coefficient along the propagation forming a quasi-lossless transmission medium, realising long-term goal of optical communications, as it brings with it a minimisation of the amplified spontaneous emission (ASE) noise build-up along the optical fibre.