Abstract: A device for optical space switching in optical networks. The optical device comprises a broad area optical waveguide section having a number of electrodes extending over at least a portion of the length of the broad area optical waveguide section. The application of an electrical signal to an electrode causes a local change in effective refractive index of the broad area optical waveguide section, thereby causing light preferentially to propagate along a predetermined path in dependence on the configuration of the electrode. In particular the broad area waveguide device is implemented in indium phosphide (InP). Also described is a method for waveguiding in the optical device.

Abstract: There is provided a semiconductor laser comprising a gain section and an adjacent Bragg section, wherein output laser light is emitted via a facet at an interface between air and the gain section, the Bragg section comprising a distributed reflecting structure having a length substantially greater than required to ensure single longitudinal mode operation of the laser in which the side-mode suppression ratio (SMSR) is 35 dB or more, thereby in use substantially suppressing optical feedback from a facet at an interface between the Bragg section and air, and wherein an interface between the Bragg section and the gain section is quantum well intermixed, thereby rendering the interface substantially anti-reflecting at the wavelength of the laser.

Abstract: A device for optical space switching in optical networks. The optical device comprises a broad area optical waveguide section having a number of electrodes extending over at least a portion of the length of the broad area optical waveguide section. The application of an electrical signal to an electrode causes a local change in effective refractive index of the broad area optical waveguide section, thereby causing light preferentially to propagate along a predetermined path in dependence on the configuration of the electrode. In particular the broad area waveguide device is implemented in indium phosphide (InP).

Abstract: In the present invention, a new design for a planar waveguide polarization splitter is based on a Mach-Zehnder interferometer (MZI) which utilises multimode interference (MMI) regions force electric beam splitting and combining, and achieves polarisation selectivity by introducing different amounts of modal birefringence to the arms of the MZI via the waveguide structure of the two arms.

Abstract: There is provided a semiconductor laser comprising a gain section and an adjacent Bragg section, wherein output laser light is emitted via a facet at an interface between air and the gain section, the Bragg section comprising a distributed reflecting structure having a length substantially greater than required to ensure single longitudinal mode operation of the laser in which the side-mode suppression ratio (SMSR) is 35 dB or more, thereby in use substantially suppressing optical feedback from a facet at an interface between the Bragg section and air, and wherein an interface between the Bragg section and the gain section is quantum well intermixed, thereby rendering the interface substantially anti-reflecting at the wavelength of the laser.

Abstract: An optical coupling mount for use in coupling light between a semiconductor waveguide device and an optical fibre comprises a silica based spot size converter (3) located on an optical bench (1) with a trench (8) and grooves (9), whereby the semiconductor device (2) can be positioned in close alignment with the spot size converter (3). The spot size converter (3) comprises a tapered upper waveguide (4) located above a non-tapered lower waveguide (6). The dimensions of the spot size converter (3) are such that a semiconductor device emitting a small, astigmatic optical beam can be efficiently coupled to a single mode fibre requiring a larger, concentric beam.