Abstract: A waveguide (10) comprises first and second light guides (12, 18) which transmit light at different wavelengths. The second light guide (18) is disposed in a tortuous path on the exterior of the first light guide (12) and preferably the tortuous path is a helix. The second light guide (18) emits light at an angle to the light emitted from the first light guide (12) and typically the light from the first light guide is emitted axially. The light from the first light guide is emitted at an angle by means of an angled refracting face (42) on the end of the second light guide (18) or by securing the end of the second light guide (18) to a conical end portion (28) of the first light guide (12).