Abstract: In one embodiment of the invention, an optical attenuation device has an input/output 6 on which a multiplexed optical input stream is received. A multiplexer/de-multiplexer (MUX/DEMUX) 2 separates the received stream into individual optical signals on individual channels and has an output/return path 12 from the MUX/DEMUX 2 for each of the channels. Reflector means 4 in each output/return path 12 reflects all or a proportion of the optical signal on the respective channel back along the output/return path 12 to the MUX/DEMUX 2. At the MUX/DEMUX, the optical signals are combined into a multiplexed stream which is output on the input/output 6. In an alternative embodiment, the device has first and second MUX/DEMUX 2, 20, an output path 12 from the first MUX/DEMUX 2, attenuation means 40 at the end of each output path 12 and return paths 120 from the attenuation means 40 to the second MUX/DEMUX 20.

Abstract: A multi cavity comb filter for interleaving or de-interleaving WDM signals has a plurality of stacked optical cavities each having substantially the same thickness. The multiple cavity arrangement provides a comb reflection response and a comb transmission response with broad peaks, so that the filter can be used for transmitting one group of channels and reflecting another group of channels at interleaved positions. The cavities are preferably formed from silicon wafers, so that existing techniques can be employed to obtain specific cavity thicknesses with sufficient accuracy and uniformity.

Abstract: The invention is directed to a waveguide termination comprising a waveguide having an end and a window through which light can pass. The end of the waveguide has an elliptical face and the elliptical face reflects light between the waveguide and the window. Preferably the optical waveguide is an optical fibre.

Abstract: A multi cavity comb filter for interleaving or de-interleaving WDM signals has a plurality of stacked optical cavities each having substantially the same thickness. The multiple cavity arrangement provides a comb reflection response and a comb transmission response with broad peaks, so that the filter can be used for transmitting one group of channels and reflecting another group of channels at interleaved positions. The cavities are preferably formed from silicon wafers, so that existing techniques can be employed to obtain specific cavity thicknesses with sufficient accuracy and uniformity.

Abstract: An optical component has at least one cell with a mirror electrode and a counter electrode, and an electrolyte disposed between the mirror and counter electrodes which includes metal ions which are depositable onto the mirror and counter electrodes. The cell is operable in a reflective and a transmissive mode by depositing different quantities of the metal ions on to the mirror electrode. An input optical signal can thus be selectively reflected, without requiring movement of mechanical components, instead relying on the flow of electrolyte ions.

Abstract: A MEMS actuator 1 comprising an actuator member 2 operably engaged by at least one actuator beam 4 and heating means 12 for heating the or each beam 4. The heating may cause expansion of the or each beam4, wherein the or each beam 4 has two ends A, A′ and the or each beam 4 is fixed at only one end A and wherein the expansion effects movement of the actuator member 2. The heating may cause thermal expansion of the beam 4 in one direction and longitudinal displacement of the beam 4 in the direction of thermal expansion, which longitudinal displacement effects movement of the actuator member 2. The beam 4 may act on the member 2 at a position in relation to a pivot point P so as to produce a torque which effects pivoting of the member 2 about the pivot point P. The actuator may have at least two actuator beams 4 and heating the at least two beams 4 may cause simultaneous expansion of the at least two beams 4, which simultaneous expansion effects movement of the actuator member 2.

Abstract: The end of an optical fibre is held in alignment with an injection laser by securing the fibre to an elongate support member whose end nearer the injection laser is then laser beam welded to a pair of slide members that have previously been secured by laser beam welding to leave a precisely dimensioned small gap between the support and slide members. The smallness of the gap minimises displacement of the fibre during the welding process. The end of the support member remote from the injection laser is secured by laser beam welding to a plastically deformable saddle.

Abstract: Light emitted from the rear facet of an injection laser diode chip is focused to a compact spot size at the photosensitive surface of a photodiode responsive to a laser bit rate of 2.5 Gbit/s by means of a substantially ellipsoidal reflector.

Abstract: An optoelectronic transducer (1) is connected with a fiber optic tail (22) by providing a casing (3) around the transducer having a flat wall (9) and by providing a termination body (20) on the fiber (22) with a thin wall flange (20A), aligning the optical axes (11, 29) and laser welding the flange to the casing.

Abstract: A laser chip is mounted on a cantilevered extension of the fibre support tube so it is immune to misalignment forces from the package. Also enables testing prior to packaging.