Abstract: Improvements relating to thermally tunable fiber optical devices have been disclosed. In one aspect, a thermally tunable fiber Bragg grating device is provided with one or more heaters to (3a, 3b) produce a desired temperature profile along the grating, and one or more supporting auxiliary heaters (5a, 5b) are provided at the edges of the grating in order to compensate for temperature drops caused by heat loss to lower temperature surroundings. In another aspect, two heating structures are thermally connected to each other, such that dissipated heat from one of the structures supports the heating effect of the other structure.

Abstract: A method and system providing dynamic contrast control in scanning line color display systems, and particularly a method and system comprising at least two modulator units is disclosed. One modulator unit is for modulating pixel information in a line to be displayed while the other one provides illumination intensity control over different pixel areas or clusters of pixels of said same line to be displayed by using a tunable diffractive grating element (TDG) in the illumination path to provide image source dependent active brightness level control, i.e. ‘dynamic contrast’, as well as a shutter function for pixels off transition periods.

Abstract: The present invention relates to methods for increasing the surface conductivity of a polymer used in tuneable diffraction grating (TDG) modulators while at the same time maintaining the total internal reflection (TIR) and transparency.

Abstract: A device and a method for reducing polarization-dependent effects in dynamical optical components based on surface modulation of a polymer gel or membrane is disclosed. The device and method modifies, removes or leads away unwanted reflections from incident light or information carrier communicating with said optical component.

Abstract: A method for locking the wavelength of a laser uses a non-planar etalon, for example a non-parallel etalon, to produce a periodic spatial interference pattern, typically in the light reflected from the non-planar etalon. At least three different portions of the interference pattern are detected to generate at least three respective detection signals. A feedback signal is generated using the detection signals, and the operating wavelength of the laser is adjusted in response to the feedback signal.

Abstract: An apparatus for locking the wavelength of a laser uses a non-planar etalon, for example a non-parallel etalon, to produce a periodic spatial interference pattern, typically in the light reflected from the etalon. The apparatus also uses a detector to detect the spatial interference pattern having at least three separate detector elements, commonly referred to as pixels. The etalon and the detector are matched to each other so that adjacent pixels detect a specific portion of the phase of the periodic interference pattern.

Abstract: In an apparatus and method for locking the wavelength of a laser, a fringe-producing optical element is disposed directly in the in the output beam from the laser. The fringe-producing optical element produces a fringe pattern in a second light beam derived from the output beam. The fringe pattern is detected by a detector unit. Signals generated by the detector unit are used to generate a laser tuning control signal that tunes the laser to a desired operating wavelength.

Abstract: An apparatus for locking the wavelength of a laser uses a non-planar etalon, for example a non-parallel etalon, to produce a periodic spatial interference pattern, typically in the light reflected from the etalon. The apparatus also uses a detector to detect the spatial interference pattern having at least three separate detector elements, commonly referred to as pixels. The etalon and the detector are matched to each other so that adjacent pixels detect a specific portion of the phase of the periodic interference pattern.

Abstract: A method for locking the wavelength of a laser uses a non-planar etalon, for example a non-parallel etalon, to produce a periodic spatial interference pattern, typically in the light reflected from the non-planar etalon. At least three different portions of the interference pattern are detected to generate at least three respective detection signals. A feedback signal is generated using the detection signals, and the operating wavelength of the laser is adjusted in response to the feedback signal.

Abstract: In an apparatus and method for locking the wavelength of a laser, a fringe-producing optical element is disposed directly in the in the output beam from the laser. The fringe-producing optical element produces a fringe pattern in a second light beam derived from the output beam. The fringe pattern is detected by a detector unit. Signals generated by the detector unit are used to generate a laser tuning control signal that tunes the laser to a desired operating wavelength.

Abstract: Waste from a nuclear power plant, containing organic ion-exchange resin containing radioactive metals, is decomposed to form volatile substances by means of oxidation in an acid, aqueous liquid (8). Radioactive metal ions thus dissolved in the liquid, which are precipitable with hydroxide, are then caused to precipitate by the addition of a hydroxide (10) at a pH value of at least 9, and the metal compounds thus precipitated are separated from at least most of the liquid. Radioactive caesium and strontium ions in this liquid are removed therefrom. The liquid (24) separated from precipitated metal compounds and freed from caesium and strontium ions is released to a recipient, with the remaining substances still dissolved in it, and the precipitated metal compounds (11k, 11s) are solidified in a deposition container (22). The ion-exchange resin preferably consists at least partially of sulphonated ion-exchange resin and the hydroxide preferably of sodium hydroxide or some other alkali metal hydroxide.