Abstract: An active optical fibre, including: a core; an inner cladding substantially surrounding the core, whereby the core and the inner cladding form an area configured to propagate pump radiation; an outer cladding comprised of at least a third material with at least a third refractive index substantially surrounding the inner cladding, the third refractive index being smaller than the second refractive index, whereby the outer cladding confines pump radiation to the core and the inner cladding; and a coating comprised of a thermally conductive material substantially surrounding the outer cladding, wherein the inner cladding is configured to reduce impact of spatial hole-burning on absorption of the pump radiation as the pump radiation propagates through the active optical fibre, and wherein the thermally conductive material of the coating supports a reduced temperature increase between the area and an outer surface of the coating.

Abstract: An acoustic field in a body of water is monitored using a coherent light field emitter applying a distributed light field across the surface of the water to be reflected, and a sensor is used to sense reflected components of the light field above the surface and to provide a signal representing information in the reflected light and related to movements in the water and caused by the acoustic field. The signal is provided from an interferometry technique and useable to derive information on the underwater acoustic field in a useful form.

Abstract: An isolated protein, for use in treatment of wounds, is characterized in that it is secreted by the organism Lucilia sericata and it exhibits proteolytic activity against FITC-casein at a pH of 8.0 to 8.5. The protein exhibits proteolytic activity against Tosyl-Gly-Pro-Arg-AMC but not against Suc-Ala-Ala-Phe-AMC, and its proteolytic activity against FITC-casein and Tosyl-Gly-Pro-Arg-AMC is inhibited by the serine proteinase inhibitors PMSF and AMPSF. The protein is also bound by immobilized aminobenzamidine.

Abstract: The present invention provides a strain gauge comprising a resistive layer. The resistive layer comprises metallic or semiconducting nanoparticles or aggregates thereof in which the nanoparticles or aggregates thereof are separated by insulating and/or semiconducting material.

Abstract: The present invention is to a method of adapting optical rare-earth-doped waveguide (10) having a plurality of transverse propagation modes, such that in use, signal gains of non-fundamental modes of the waveguide are attenuated relative to a signal gain of a fundamental mode of the waveguide. The waveguide (10) has a light-guiding region (45) defined by a refractive index-modifying dopant, such as Ge, which has a thermal diffusion coefficient at temperature T in the waveguide greater than a thermal diffusion coefficient of the rare-earth dopant at temperature T. The method comprises heating the waveguide (10) at the temperature T such that a concentration profile of the refractive index-modifying dopant becomes broader than a concentration profile of the rare-earth dopant.

Abstract: The present invention provides a method and apparatus for obtaining a measure of the chromatic dispersion of a fibre bragg grating, the method comprising: disposing the grating in a reflection arm of an interferometer; inputting probe laser light into the interferometer; stepping the wavelength of the light across the reflection bandwidth of the grating, while at each step modulating the wavelength by a wavelength modulation less than the size of the respective step, and thereby producing a resulting phase modulation; and demodulating the phase modulation and determining therefrom a measure of the chromatic dispersion.

Abstract: In the method of detecting a localized sun gear fault, in the operation of an epicyclic gear train having ring, planet and sun gears, and a planet carrier, the steps that include detecting sun gear vibrations transmitted through each planet gear, computing separated averages of such detected vibrations, phase shifting the averages to account for the differences in gear meshing positions, and re-combining the phase shifted averages to produce a modified average value of the sun gear vibration.

Abstract: An improved optical modulator and photodetector suitable for high frequency operation and compatible with monolithic microwave integrated circuit technology. Typical implementations use a reversed biased diode containing not intentionally doped (NID) optically active region sandwiched between conductive layers of p-doped and n-doped semiconductor layers, respectively. With monochromatic optical radiation incident upon the device a photocurrent (comprising of an electron-hole pair created for each photon absorbed) can be generated using the optical nonlinearity of the multiple quantum well structure inside the active region. This photocurrent can be used in an external circuit to provide photocurrent feedback to the device itself.

Abstract: A system for information transmission having a plasma antenna, including an electrodeless plasma tube, and a power source effective to generate an electromagnetic field to cause ionization of material within the tube so as to form the antenna for one or both of either sending or receiving signals, wherein the electromagnetic field is applied to a portion only of the tube. The system preferably includes a terminal arranged about a base of the tube or establishing the electromagnetic field upon application of power from the power source, to induce surface wave ionization within the tube.

Abstract: The present invention is for an improved modulator and detection device that use reversed biased diodes containing not intentionally doped (NID) optically active regions sandwiched between conductive layers of p-doped and n-doped semiconductor layers. A photo-current is generated using the optical non-linearity of multiple quantum structures inside the active region and that can be used in an external circuit to provide feedback to the device itself. This is commonly referred to as the self electro-optic effect device (SEED) where the applied electric field modulates the absorption (excitonic in nature due to the reduced dimensionality of the quantum well) of the active layer by the use of the quantum confined Stark effect. The present invention seeks to improve on known devices by separating the photo-current from the perpendicular biased electric field so as to produce a four electrical port device, by simultaneously applying non-parallel fields.

Abstract: The method of detecting a fault in an epicyclic gear train having ring, planet and sun gears, and a planet carrier, the steps including locating a vibration monitoring detector in association with the ring gear; operating the gear train to produce vibration detected by the detector to obtain an overall vibration signal; and timewise dividing the overall vibration signal into contributions from each planet gear.