An optical fibre core (39) having a reflective coating (33) along a first part of its length such that electromagnetic radiation may travel along the first part of the optical fibre by means of reflection, and further having a cladding (37) along a second part of its length, the cladding having a refractive index suitable for permitting the electromagnetic radiation to travel along the second part of the optical fibre. The invention also provides a fibre optic coupling arrangement for coupling a light pipe to a clad optical fibre, the coupling arrangement comprising a light pipe comprising an optical fibre core having a reflective coating and a clad optical fibre comprising an optical fibre core with cladding surrounding the core, the optical fibre core of the light pipe being optically joined to the optical fibre core of the clad optical fibre such that electromagnetic radiation is able to travel from the light pipe to the clad optical fibre, wherein tapered cladding is provided in the region where the light pipe is optically joined to the clad optical fibre.