Abstract: The polarizer is formed on a silicon rib waveguide (4) having an upper face and two side faces, and comprises a section of the silicon rib waveguide (4) with a buffer layer (6) and a light absorbing layer (7) on either the upper face of the rib or at least one side face of the rib. The buffer layer (6) has a refractive index similar to that of the waveguide (4) such that light traveling along the waveguide (4) and incident upon the respective face thereof passes into the buffer layer (6) and then into the light absorbing layer (7) so either the TM (transverse magnetic) or TE (transverse electric) mode of the light traveling along the waveguide is attenuated.

Abstract: The integrated light absorber comprises a light chamber integrated in an optical chip, the chamber having upper and lower walls lying substantially parallel to the chip and peripheral walls extending there between and a light input port in a peripheral wall for receiving light to be absorbed, e.g. from a rib waveguide. At least one of the walls have light absorbing properties and the chamber is shaped so that the majority of light which enters the chamber through the light input port undergoes multiple reflections and so is absorbed by the walls of the chamber. Circular and star-shaped chambers are described.

Abstract: A connection between an integrated optical waveguide and an optical fibre has a layer of silicon in which a rib waveguide is formed separated from a substrate by a layer of silicon dioxide. A V-groove is formed in the substrate for receiving an optical fibre, and the V-groove is arranged to align the optical fibre at a predetermined angle with respect to the waveguide. The rib waveguide and the underlying layer of silicon dioxide are formed to overhang the end of the V-groove so that the end of the waveguide is in close proximity with the end of an optical fibre positioned in the V-groove. A method of forming a connection, in which the V-groove is etched using a material which etches the substrate material as opposed to the layer of silicon dioxide, is also disclosed. Finally, a method of connecting an integrated optical waveguide to an optical fibre using a connection as described above is disclosed.