Abstract: Simple polarization independent wavelength tuning components (filters) employ a filter element, such as a Fabry-Perot etalon element, which is such that light input thereto undergoes two element transitions with orthogonal polarization states before being output, in order to suppress polarization noise. The element may be mounted for rotation about a single axis. In one arrangement, two etalon filters (20, 21), are separated by a half wave plate (22) providing the necessary polarization rotation. The two etalon filters and the half wave plate comprise a single element rotatable about the single axis.

Abstract: A circularly symmetric reinstatement sheathed optical fibre splice butt joining the ends of two acrylate sheathed glass optical fibres is made by a method that includes the step of immersing the spliced fibres (14) in dichloromethane (64) to cause the acrylate to swell and longitudinally expand to close the gap (42) in the sheathing (41) left by the splicing process. The sheathing is clamped in this position while the solvent evaporates. The residual gap, which is comparable in length with the sheath diameter, is protected by the application of a drop of uncured resin which capillary forces constrain to assume a circularly symmetric form until the resin is cured.

Abstract: A single mode optical fibre preset attenuator is made by forming a fusion splice (2) between a length of silica fibre possessing no internal waveguiding structure to a length (1) of single mode optical fibre. Then the silica fibre is cut to a predetermined length to form a short stub (3) which is fusion spliced to a second length (4) of single mode fibre. The fusion splicing equipment may subsequently be used to heat soften the central region of the stub to enable it to be shortened or lengthened to fine tune the attenuation provided.

Abstract: When a pair of plastics sheathed glass optical fibres (1, 2) is joined by a fusion splice there is a length of bare fibre between where the original sheathing of one fibre terminates and where that of the other begins. This gap is filled with reinstatement sheathing (5, 5b) which is fused to the original sheathing using a length (4) of heat-shrink tubing as a mould. The heat-shrink tubing is then removed to leave a smooth profile for the spliced fibre.

Abstract: A pair of interlocking single filament or multifilament loops (6,7) are mounted on the opposed operating ends (4,5) of a pliers action type hand tool. An aperture is formed between the two loops through which an optical fibre (31) complete with soft plastics primary coating (32) is inserted. The loops are tensioned by operation of the tool, and while this tension is maintained the fibre is removed causing the coating to be stripped off by the tightened loops.