Abstract: A sensor strip comprises an elongate member that is segmented; the segments are defined by longitudinal and transverse grooves, such that the adjacent segments are hinged together; the longitudinal grooves define a central column and outer columns of segments; the segments in the outermost columns are tapered outwardly; and a pressure sensitive sensor is mounted in a plurality of the segments in the central column. A sensor strip of the invention can be used by introducing it under a bandage and recording the pressure at each of the pressure-sensitive sensors.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: A method of assembling an optical sensor for measuring pressure and/or temperature is disclosed. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The method comprises fabricating a sensor element formed of a pill having an enclosed cavity, bonding the pill to a front end of a spacer, bonding a lens to the back end of the spacer to form the optical assembly, aligning an optical fiber to the optical assembly, and fixing the fiber in position by fusing the fiber to the lens.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: A method of assembling an optical sensor for measuring pressure and/or temperature is disclosed. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The method comprises fabricating a sensor element formed of a pill having an enclosed cavity, bonding the pill to a front end of a spacer, bonding a lens to the back end of the spacer to form the optical assembly, aligning an optical fibre to the optical assembly, and fixing the fibre in position by fusing the fibre to the lens.

Abstract: An optical sensor is disclosed for measuring pressure and/or temperature. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The optical sensor comprises an optical assembly having a sensor element, a spacer and a lens arranged along the optical axis. The sensor element is spaced from the lens by the spacer. An optical fiber is coupled to the optical assembly for illuminating the sensor element. The optical assembly is resiliently mounted in a housing such that the optical assembly is insulated from shock to the housing. There is also disclosed a method of assembling the optical sensor.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: An optical sensor is disclosed for measuring pressure and/or temperature. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The optical sensor comprises an optical assembly having a sensor element, a spacer and a lens arranged along the optical axis. The sensor element is spaced from the lens by the spacer. An optical fibre is coupled to the optical assembly for illuminating the sensor element. The optical assembly is resiliently mounted in a housing such that the optical assembly is insulated from shock to the housing. There is also disclosed a method of assembling the optical sensor.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: An optical sensor having a sapphire body is disclosed. A hollow in the sapphire body defines a surface which is used as a surface of a Fabry-Perot cavity. Interferometry is used to detect changes in the length of the Fabry-Perot cavity, and hence changes in, for example, the temperature or pressure of an environment in which the sensor is placed.

Abstract: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Abstract: A doped slab region is described for use around a ridge waveguide, for controlling the refractive index of the waveguide material. Instead of simply diffusing dopant in from a surface of the slab region adjacent the waveguide, an area of the slab region is etched and dopant diffused in from a side face of the etched region. Thus, the dopant profile is established from a horizontal direction, allowing the profile to be controlled. A simple vertically uniform doping profile can thus be provided, leading to a vertically uniform current density, or an anisotropic wet etch can be applied after the initial etch to provide a profile which concentrates the current density at a selected height in the slab region.

Abstract: A method of fabricating an integrated optical component on a silicon-on insulator chip comprising a silicon layer (1) separated from a substrate (2) by an insulating layer (3), the component having a first set of features, eg a rib waveguide (5) at a first level in the silicon layer (1) adjacent the insulating layer (3) and a second set of features, eg a triangular section (5B) at a second level in the silicon layer (1) further from the insulating layer (3), the method comprising the steps of: selecting a silicon-on-insulator chip having a silicon layer (1) of sufficient thickness for the first set of features; fabricating the first set of features in the silicon layer (1) at a first level in the silicon layer; increasing the thickness of the silicon layer (1) in selected areas to form a second level of the silicon layer (1) over part of the first level; and then fabricating the second set of features at the second level in the silicon layer (1).

Abstract: An optical waveguide structure formed on an optical chip comprising a first waveguide layer 3 of a first material supported on a substrate 7 and a second waveguide layer 6 of a second material supported on the first waveguide layer 3. The first waveguide layer 3 is separated from the substrate 7 by an optical confinement layer 8 and the second waveguide layer 6 is separated from the first waveguide layer 3 by an etch-stop layer 9. The etch-stop layer 9 is thin compared to the thickness of the first waveguide layer 3 and/or the second waveguide layer 6 and is of a material which enables it to act as an etch-stop when features are etched in the second waveguide layer 6.

Abstract: An integrated optical circuit is formed in a silicon layer and supported on a substrate, and a portion of the silicon layer is substantially thermally isolated from the substrate by extending over a recess in the substrate, e.g. in the form of a bridge. Temperature control means are provided to control the temperature of the portion of the silicon layer or of a device provided thereon. A thermal expansion gap may be provided in the portion to accommodate thermal expansion of the portion relative to the substrate.

Abstract: A method of providing a point to point connection between two electrical circuit boards (23, 23′) in which a plurality of pairs of optical transceivers are provided, one transceiver of each pair being formed on a first silicon-on-insulator chip (2) in electrical contact with a first electrical circuit board (23), and the other transceiver of each pair being formed on a second silicon-on-insulator chip (2′) in electrical contact with a second electrical circuit board (23′). Each optical transceiver comprises a branched rib waveguide comprising a common stem (10, 26) and first and second branches (14, 12) extending from the common stem (10, 26); a fiber connector (20) for receiving an optical fiber (22) in communication with the stem (10, 26) of the branched rib waveguide; a light source (4) in communication with the first branch (14) of the branched rib waveguide; and a light receiver (6) in communication with the second branch (12) of the branched rib waveguide.

Abstract: An interferometer is integrated on an optical chip. The optical chip is formed on a layer of silicon separated from a substrate by a layer of insulating material. The optical chip includes an integrated fiber connector for connecting the optical chip to one or more optical fibers. The fiber connector includes a groove formed in the substrate for receiving an optical fiber and a waveguide for transmitting light to or from the fiber connector. The waveguide includes rib waveguides formed in the layer of silicon and at least one phase modulator for altering the phase of light traveling along one of the rib waveguides. This arrangement forms an interferometer in which light transmitted along different optical paths can be combined and the effective path length of at least one of the optical paths can be altered by the phase modulator.

Abstract: A point to point optical link from a transmitter (1) to, a receiver (2) via an optical fiber (3), the transmitter (1) comprising light sources (4) providing signals of different wavelengths and a multiplexer (6) combining the signals onto a single channel for transmission along the optical fiber (3), and the receiver (2) comprising light sensors (8) and a demultiplexer (10) for separating the signals of different wavelengths and directing each to a respective light sensor (8). The output of the transmitter (1) is temperature dependent but arranged so that the change in wavelength with respect to temperature for each of the signals is similar, and the demultiplexer (10) being adjustable so that its response to signals with respect to their wavelength can be actively tuned so as to follow variations in the wavelength of the signals received.

Abstract: An optical waveguide, such as a rib waveguide, having a first portion (7) to which a dopant (9) and/or a metal layer (10) is applied to enable an optical property of a second portion of the waveguide to be altered, the first portion (7) having a structure, e.g. being corrugated, the geometry of which is such as to prevent an optical wave being carried in the first portion (7). The dopant (9) and/or metal layer (10) can thus be positioned close to the second portion which carries the optical wave without causing perturbation, e.g. attenuation and/or polarization, of the optical wave.