Abstract: A system that implements a data storage service may store data for a database table in multiple replicated partitions on respective storage nodes. In response to a request to back up a table, the service may back up individual partitions of the table to a remote storage system independently and (in some cases) in parallel, and may update (or create) and store metadata about the table and its partitions on storage nodes of the data storage service and/or in the remote storage system. Backing up each partition may include exporting it from the database in which the table is stored, packaging and compressing the exported partition for upload, and uploading the exported, packaged, and compressed partition to the remote storage system. The remote storage system may be a key-value durable storage system in which each backed-up partition is accessible using its partition identifier as the key.

Abstract: A distributed sensing apparatus based on Optical Time Domain Reflectometry, OTDR, including an optical source; an optical splitter in optical communication with the optical source, the optical splitter having first and second outputs; a sensing fibre in optical communication with the first output of the optical splitter; a combining unit arranged to combine a reference signal derived from the second output of the optical splitter with a backscattered signal derived from the sensing fibre, wherein the combining unit comprises one or more 3×3 fused fibre couplers; and a signal processing unit configured for processing information derived from the combining unit so as to provide distributed sensing data. The combining unit includes a polarization diversity arrangement including one or more polarization sensitive elements.

Abstract: A sensor system for detection and localisation of changes in or values for at least one environmental condition includes a source of pulses of electromagnetic radiation, wherein the source is configured to emit electromagnetic radiation at a plurality of different wavelengths, an optical fibre in optical communication with the source of pulses, wherein the optical fibre includes a fibre Bragg grating having a reflectance and/or transmittance which varies in dependence on the at least one environmental condition, and a detection unit for detecting electromagnetic radiation which has been reflected or transmitted by the fibre Bragg gratings, wherein the detection unit is configured for detecting electromagnetic radiation at the plurality of wavelengths, such that a spectral response can be determined for different spatial regions along the optical fibre, wherein a change in or value for the environmental condition at a spatial region may be determined by monitoring the respective spectral response.

Abstract: An apparatus for digitizing an optical signal comprises: an optical detector to detect an optical signal and to generate an electric signal corresponding to the optical signal; an envelope curve detector to determine the amplitude of the electric signal or a modified electric signal resulting from the electric signal, and to supply an amplitude signal corresponding to the amplitude; an analog to digital converter to digitize the amplitude signal and to supply a corresponding digitized amplitude signal; and a variable voltage source to calibrate the envelope curve detector.

Abstract: A distributed sensing apparatus based on Optical Time Domain Reflectometry, OTDR, including an optical source; an optical splitter in optical communication with the optical source, the optical splitter having first and second outputs; a sensing fibre in optical communication with the first output of the optical splitter; a combining unit arranged to combine a reference signal derived from the second output of the optical splitter with a backscattered signal derived from the sensing fibre, wherein the combining unit comprises one or more 3×3 fused fibre couplers; and a signal processing unit configured for processing information derived from the combining unit so as to provide distributed sensing data. The combining unit includes a polarization diversity arrangement including one or more polarization sensitive elements.

Abstract: A sensor system for detection and localisation of changes in or values for at least one environmental condition comprises a source of pulses of electromagnetic radiation, wherein the source is configured to emit electromagnetic radiation at a plurality of different wavelengths, an optical fibre in optical communication with the source of pulses, wherein said optical fibre includes one or more fibre Bragg gratings having a reflectance and/or transmittance which varies in dependence on the at least one environmental condition, and a detection unit for detecting, at a plurality of different times, electromagnetic radiation which has been reflected or transmitted by at least one of the fibre Bragg gratings, wherein the detection unit is configured for detecting electromagnetic radiation at the plurality of different wavelengths, such that a spectral response can be determined for different spatial regions along the optical fibre, wherein a change in or value for the environmental condition at a spatial region may

Abstract: Device for spatially resolved measurement of temperature, strain, or both by Brillouin scattering, with a laser light source (1) for generating a laser radiation, an optical fiber (5) used for the measurement, into which the laser radiation can be coupled in and from which Brillouin signals generated by Brillouin scattering can be coupled out, sensors for detecting the coupled-out Brillouin signals, evaluators for determining spatially resolved from the detected Brillouin signals the temperature, strain, or both of sections of the optical fiber (5), a polarization beam splitter (10, 11) capable of splitting the coupled-out Brillouin—signals into two components (12, 13) having mutually different polarizations, and an optical coupler (16, 17) for admixing a laser radiation to the Brillouin signal.

Abstract: Device for spatially resolved measurement of temperature and/or strain by Brillouin scattering, with a laser light source (1) for generating a laser radiation, an optical fiber (5) used for the measurement, into which the laser radiation can be coupled in and from which Brillouin signals generated by Brillouin scattering can be coupled out, sensors for detecting the coupled-out Brillouin signals, evaluators for determining spatially resolved from the detected Brillouin signals the temperature and/or strain of sections of the optical fiber (5), a polarization beam splitter (10, 11) capable of splitting the coupled-out Brillouin-signals into two components (12, 13) having mutually different polarizations, and an optical coupler (16, 17) for admixing a laser radiation to the Brillouin signal.

Abstract: A power supply for a retina implant at least partly located in the interior of a patient's eye is described. The power supply comprises a first transmission coil (4, 23), a second transmission coil (5, 24). The power supply further comprises a signal generation unit adapted for generating a first high frequency signal and a second high frequency signal, and for applying the first high frequency signal to the first transmission coil and the second high frequency signal to the second transmission coil, the second high frequency signal being phase shifted relative to the first high frequency signal. The first transmission coil is adapted for transmitting the first high frequency signal, and the second transmission coil is adapted for transmitting the second high frequency signal.

Abstract: A power supply for a retina implant at least partly located in the interior of a patient's eye is described. The power supply comprises a first transmission coil (4, 23), a second transmission coil (5, 24). The power supply further comprises a signal generation unit adapted for generating a first high frequency signal and a second high frequency signal, and for applying the first high frequency signal to the first transmission coil and the second high frequency signal to the second transmission coil, the second high frequency signal being phase shifted relative to the first high frequency signal. The first transmission coil is adapted for transmitting the first high frequency signal, and the second transmission coil is adapted for transmitting the second high frequency signal.