Abstract: A control (20) and a method of controlling a tunable laser having a gain section (4), a phase change section (5) and a segmented Bragg grating reflector section (6) comprising a series of grating units (9-17) each of a different pitch, and an electrode (9a-17a) associated with each grating so that an electrical current is applicable to each individual grating. The control (20) includes a plurality of digitally controlled sources (31, 32) of electrical current which are each connected to switch means (33 or 35, 36) operable to independently connect each of said sources (31, 32) to a respective electrode (e.g. 11a or 12a) associated with a grating (e.g. 11 or 12) which is one of a subset of consecutive gratings (e.g. 11 & 12) selected from said series of grating units (9-17).

Abstract: A glass fixative composition for bonding glass materials to non-glass materials is provided. The fixative composition is selected for its thermal expansion coefficient, its viscosity, its adhesion to glass, melting point, and bond strength. The glass fixative is in particular useful for bonding optical fibers to metallic materials such as Kovar. The low melting point of the glass fixative enables localized heating methods to be used, in particular, as Kovar is a ferromagnetic material, induction heating can be used to form a bond. The bond formed provides a compressive joint which enables the fiber to be hermetically fixed in position.

Abstract: A strain sensor comprises an optical waveguide having a plurality of reflecting structure (Bragg grating) along its length. Each structure reflects light at a different characteristic wavelength (&lgr;1 to &lgr;n+1) which changes in dependence on a change of physical length of at least part of the reflecting structure. The reflectivity of reflecting structures which reflect at characteristic wavelengths which are adjacent to each other (&lgr;1 and &lgr;2 or &lgr;n and &lgr;n+1) are configured to be different such that the intensity of light reflected from adjacent structures can be used to discriminate between them.

Abstract: A method of producing an optical grating component including only a single continuous grating field formed in a longitudinal waveguide rib, the method including the steps of defining a grating in an optic chip including a portion thereof through which the longitudinal waveguide rib is to extend, and then defining the lateral edges of the longitudinal rib in the optic chip, whereby any portion of the grating extending laterally beyond the lateral width of the rib is removed in the step of defining the lateral edges of the rib leaving a single continuous grating field that has straight lateral grating boundaries that are laterally aligned with the straight lateral edges of the rib.

Abstract: A system for detecting an optical output at a predetermined frequency, the system comprising: a plurality of optical guides for introducing an optical signal at said frequency into an input end of a dispersive optical component at each of a plurality of introduction sites corresponding to said optical guides; a detector located at the output end of the dispersive optical component and arranged to detect the optical power level of the optical signal introduced at each introduction site; means for establishing an optical power profile by interpolation of the optical power levels; and selection means for selecting the input optical guide at the introduction site at which the generated optical power level is spatially closest to the peak of the optical power profile.

Abstract: A wavelength-dispersive device for processing a multi-channel optic signal, the device including an optic chip defining first and second diffraction gratings coupled via a first free propagation region, the second diffraction grating coupled at its output end to an array of light-receiving elements via a second free propagation region, each light-receiving element positioned to selectively receive a respective channel of the multi-channel signal, and wherein the first free propagation region includes a spatial filter defined by selective doping of the optic chip so as to preferentially transmit a selected portion of the output from the first diffraction grating to the second diffraction grating and thereby reduce cross-talk at the array of light-receiving elements.

Abstract: A method for holding an end of at least one optic fibre in alignment for optical communication with an end of a respective optic element at a side edge of an optic chip; the method including the steps of: providing a fibre support supporting at least one optic fibre; assembling the fibre support and the optic chip so as to align the end of the at least one optic fibre with the end of the respective optic element at the side edge of the optic chip, wherein the fibre support includes a first portion that is configured to extend beyond the side edge over the optic chip when the end of the at least one optic fibre is aligned with the end of the respective optic element at the side edge; and then bonding said first portion of the fibre support to the optic chip to secure the fibre support to the optic chip.