Abstract: An optical shape sensing method is provided.

Abstract: An interferometric fluid sensing system is provided.

Abstract: A fibre optic sensing device is provided. The fibre optic sensing device includes a plurality of optical fibre portions, wherein each optical fibre portion is arranged to receive laser light from a common laser and reflect the laser light to a common detector. Each optical fibre portion includes a first reflector spaced from a distal end of the optical fibre portion and a second reflector at the distal end. Each optical fibre portion also includes a sensor provided at the distal end of the optical fibre portion. The sensor includes a third reflector the position of which varies depending on a value of a property being sensed. A distance between the first and second reflectors is different for each of the optical fibre portions.

Abstract: A fibre optic sensing device is provided. The fibre optic sensing device comprises a plurality of optical fibre portions, wherein each optical fibre portion is arranged to receive laser light from a common laser and reflect the laser light to a common detector, wherein each optical fibre portion comprises a first reflector spaced from a distal end of the optical fibre portion and a second reflector at the distal end, wherein each optical fibre portion comprises a sensor provided at the respective distal end of the optical fibre portion, the sensor comprising a third reflector the position of which varies depending on a value of a property being sensed, wherein a distance between the first and second reflectors is different for each of the optical fibre portions.

Abstract: This disclosure relates to hollow fibre waveguide spectroscopic gas cells built using connectors and the method for making them. The connectors are used to construct gas cell end pieces which allow gas and light to enter the hollow fibre waveguide simultaneously thus creating a gas cell. The connectors comprise a window which intersects or is in close proximity to a junction of bores within the connector, the bores transmitting gas through the connector to or from the hollow fibre waveguide. Connectors may also be used to connect two sections of fibre together in order to produce longer gas cells which enhance the signal-to-noise ratio of spectroscopic measurements. The window, which is at least partially transparent at the wavelength of the light used for spectroscopic purposes, is affixed so as to maintain a gas tight seal for the gas cell.

Abstract: A gas analyzer and a corresponding method is provided to measure the concentration of formaldehyde within enclosed environments such as within buildings comprising an ultraviolet light source, a sample chamber, a detector. The detector measures the intensity of light received by photosensors within a measurement range of wavelengths, and at least one reference range of wavelengths. Advantageously, the concentration of formaldehyde is determined taking into account fluctuations in the intensity of light emitted by the light source, and in the presence of any interferents such as nitrogen dioxide.

Abstract: A gas analyser is provided to measure the concentration of formaldehyde within enclosed environments such as within buildings comprising an ultraviolet light source, a sample chamber, a detector. The detector measures the intensity of light received by photosensors within a measurement range of wavelengths, and at least one reference range of wavelengths. Advantageously, the concentration of formaldehyde is determined taking into account fluctuations in the intensity of light emitted by the light source, and in the presence of any interferents such as nitrogen dioxide. A method of measuring the concentration of formaldehyde in enclosed environments is also presented.