Fibre optic communication systems have traditionally carried data using binary (on-off) encoding of the light amplitude. However, next generation systems will exploit both the amplitude and phase of the optical carrier to achieve higher spectral efficiencies and thus higher overall data capacities 1,2. Although this approach requires highly complex transmitters and receivers, the increased capacity and many further practical benefits that accrue from a full knowledge of the amplitude and phase of the optical-field 3 , more than outweigh this additional hardware complexity and can greatly simplify optical network design. However, use of the complex optical-field gives rise to a new dominant limitation to system performance, namely nonlinear phase noise 4,5. A device for removal of this noise therefore becomes of great technical importance. Here we report the development of the first practical ('black-box') all-optical regenerator capable of removing both phase and amplitude noise from binary phase-encoded optical communication signals.

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Abstract:We report on the progress of bismuth oxide glass holey fibers for nonlinear device applications. The use of micron-scale core diameters has resulted in a very high nonlinearity of 1100 W -1 km -1 at 1550 nm. The nonlinear performance of the fibers is evaluated in terms of a newly introduced figure-of-merit for nonlinear device applications. Anomalous dispersion at 1550 nm has been predicted and experimentally confirmed by soliton self-frequency shifting. In addition, we demonstrate the fusionsplicing of a bismuth holey fiber to silica fibers, which has resulted in reduced coupling loss and robust single mode guiding at 1550 nm. 440-442 (2003)

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We present simple scaling rules to optimize the design of 2R optical regenerators relying on Self-Phase Modulation in the normal dispersion regime and associated offset spectral filtering. A global design map is derived which relates both the physical parameters of the regenerator and the properties of the incoming signal to the regeneration performance. The operational conditions for optimum noise rejection are identified using this map and a detailed analysis of the system behavior under these conditions presented. Finally, we demonstrate application of the general design map to the design of a regenerator for a specific 160 Gb/s system.