Abstract: A waveguide comprising photonic crystal fibre terminated by a re-imaging device. The re-imaging device may, for example, be a length of multimode fibre. Connectors for such waveguides are also disclosed. A method of attaching a connector to a photonic crystal fibre is also disclosed. The method comprises terminating the photonic crystal fibre by splicing multimode fibre onto an end of the photonic crystal fibre to form a terminated photonic crystal fibre end, locating a ferrule on the terminated photonic crystal fibre such that there is a predetermined length of multimode fibre between the splice and the output end of the ferrule, and locating the ferrule within a connector body.

Abstract: An optical amplifier is described that comprises at least two sections of amplifying optical fibre and pumping means for optically pumping the amplifying optical fibre. Optical fibre support means, for example a channel or channels in a substrate, are also provided to hold the two or more sections of amplifying optical fibre substantially straight during use. The optical fibre support means also includes a means for coupling light between the at least two sections of amplifying optical fibre. The at least one amplifying optical fibre may comprise an Erbium doped core to provide an erbium doped fibre amplifier (EDFA).

Abstract: Optical circuits for optical amplifier input and output stages are described. The input stage circuit (42) comprises a first optical waveguide (46) for carrying a signal beam to be amplified, a second optical waveguide (62) for carrying a pump beam, a beam combining means (58) optically coupled to the first and second optical waveguides (46, 62) for producing a combined signal/pump beam, and means for optically coupling the combined signal/pump beam into an amplifying optical fibre (63). The output stage circuit (44) comprises a first output optical waveguide (64), an optical fibre attachment means arranged to receive an amplifying optical fibre (63) and an optical fibre attachment means arranged to receive an output optical fibre (76) wherein light from the amplifying optical fibre (63) is optically coupled to the output optical fibre (76) via the first output optical waveguide (64).