It has been recently demonstrated both theoretically and experimentally that any optical pulse that is amplified in a normally dispersive optical fibre evolves asymptotically in a self-similar fashion into a pulse with a parabolic intensity profile and a positive linear chirp.
We propose to take advantage of these specific pulses, known as similaritons, in the fields of telecommunications and high-power ultra-short pulse generation. The generation of ghost-pulses in zero bit slots is one of the major limitations to high-rate telecommunications.
We propose to use the spectral properties of similaritons, in conjunction with offset spectral filtering, as the basis of a 2-R optical regenerator with which to reduce the ghost-pulse energy and to restore the signal quality.
We will focus our work on generating similaritons in specially tailored rare-earth-doped amplifiers. The optimum design of the amplifier/filter will be found by a numerical approach and the regenerator built and tested within a 40Gbit/s test bed.
In order to extend our work to multi-wavelength a two-stage amplifier system will also be constructed and demonstrated. In parallel with this work, we will also attempt to exploit the unique properties of the similariton in the field of ultra-short high-power pulse generation.
Since similaritons are able to resist most of the deleterious nonlinear effects acting it is possible to use them in conjunction with novel large core high power fibres to increase the output power levels that can be generated in ultra-short pulse fibre amplifiers and lasers.
We plan to design and fabricate novel dual clad, rare-earth doped photonic crystal fibres and band gap fibres optimised for similariton effects, and to investigate their use in similariton amplifier chains and similariton lasers.
Our ultimate targets are to generate 5 microJoule 100fs similariton pulses from an amplifier system and 200nJ, 50fs pulses from a passively mode-locked similariton laser.
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