Nonlinear polarisation effects in fibre Bragg gratings: experiment and theory

Summary form only given. Recently we demonstrated the operation of an all-fibre nonlinear AND gate based on polarisation coupled gap solitons. In this system when a single pulse was incident upon the grating it was reflected irrespective of its polarisation. However when two pulses with orthogonal polarisations were incident upon the grating a coupled gap soliton was formed which was able to propagate through the grating. In addition to the AND gate we also looked at the polarisation dynamics of a single linearly polarised pulse propagating in a fibre Bragg grating. Briefly we used high nanosecond pulses obtained from a sequence of cascaded fibre amplifiers. These pulses were launched into a 8 cm apodised fibre Bragg grating and at the output light from the two orthogonal polarisations were directed onto a fibre coupled photodiode and a sampling oscilloscope with a time resolution of /spl sim/ 50 ps.