A rotary optical position encoder includes a source of a linear-polarized light beam, a polarization-sensitive detector, and a rotating retarder disposed for rotation between the source and the detector. The retarder is configured and operative to produce a polarized exit beam whose polarization state rotates at a rate greater than a rotation rate of the retarder, thereby for increased resolution over a similar encoder using a rotating polarizer element. In an example, when polarized light is incident upon a rotating half-wave retarder, the transmitted beam's polarization axis rotates at twice the rate of retarder rotation, resulting in an electrical detector output that varies four times per revolution. Resolution is improved accordingly, as a given detected increment at the output is produced by only one-half the physical rotation increment required for a simple polarizer.

An opto-magnetic rotary position encoder includes a polarization optical encoder and a magnetic encoder, both configured for on-axis placement and operation with respect to a rotational axis of a rotating component. A polarization sensor digital control block and a magnetic sensor digital control block are configured and operative to combine polarizer channel position data and magnetic channel position data in a manner providing for one or more of (1) redundancy, (2) calibration, (3) monitoring performance of one channel in relation to the other channel, or (4) compensation or correction of one channel based on the other channel.

The optical fiber sensor device comprises a probe light supply unit, an optical fiber sensor unit, and a polarization state measuring unit. The probe light supply unit generates and outputs a polarization switched light beam by alternately switching a polarized CW light beam in polarization directions orthogonal to each other with elapse of time. The optical fiber sensor unit includes a loop-state optical fiber into which the polarization switched light beam is input and which outputs a light wave reflecting a change of birefringence according to a stress applied from an outside in the polarization switched light beam. The polarization state measuring unit observes polarization states of the respective light waves propagating clockwise and counterclockwise through the optical fiber. The polarization state measuring unit calculates an angular velocity vector .sub.b defined by an equation that specifies a relationship between a temporal change rate ds.sub.out(t)/dt of a Stokes vector s.sub.out(t) giving a polarization state of the light wave from the optical fiber and the Stokes vector s.sub.out(t) for each of the clockwise and counterclockwise light waves. The angular velocity vector .sub.b gives a direction of a rotation center axis and a rotation angular velocity of the Stokes vector s.sub.out(t).

A fiber optical sensor and methods for sensing a physical quantity such as rotation using the same. The sensor has an optical fiber supporting propagation of light that is configured as an interferometer. One or more segments of the optical fiber, where the segments may be non-contiguous, are poled in such a manner that a phase shift in light propagating through the fiber is created in response to application of a voltage to an electrode thereby inducing an electric field across a poled segment of the fiber. A phase modulator comprising multiple poled segments is additionally described. Applying phase-shifting effects differentially across poled segments of optical fibers of an array of optical fibers may also allow for steering an optical beam.

Disclosed is an optical fiber interferometric system including a light source (1), a fiber optic coil (8), a coil splitter (3), a photodetector (2), and a polarization filtering unit. According to an embodiment, the polarization filtering unit includes a first waveguide polarizer (51), at least one second thin-plate polarizer (52) and an optical waveguide section (12), the at least one second polarizer (52) being disposed in the Rayleigh zone between a first waveguide end (21) of the first polarizer (51) and a second waveguide end (22) of the optical waveguide section (12).

A position detecting apparatus includes: a main gear on a main shaft rotatable around a shaft center, and rotating with the main shaft; two or more auxiliary gears connected to the main gear, configured with a different number of teeth than the main gear, and configured to have a different number of teeth than each other; magnetic angle sensors respectively provided on the auxiliary gears, and configured to detect rotating angles of the auxiliary gears; a first polarization plate provided on the main shaft, and rotating with the main shaft; counter polarization plates provided at positions facing the first polarization plate, and having polarization angles deviated from each other by 45; a light source irradiating the first polarization plate and the counter polarization plates; and light receptors detecting light irradiated from the light source and passing through the first polarization plate and the counter polarization plates.

The present invention relates to a compressed sensing-based Brillouin frequency domain distributed optical fiber sensor device, and includes: a probe light generation unit that generates probe light using light output from a light source unit and transmits the probe light through one end of a sensing optical fiber; a compressed sensing light generation unit that generates compressed sensing light having a complex signal waveform, in which a plurality of different frequency signals are compressed, using the light output from the light source unit; an optical circulator that receives the compressed sensing light through an input terminal, transmits the same to an output terminal connected to the other end of the sensing optical fiber, and outputs, to a detection terminal, light scattered in the sensing optical fiber and incident through the output terminal; a light detection unit that detects Brillouin scattered light received through the detection terminal; a compressed sensing signal generation unit that generates a compressed sensing signal so that the compressed sensing light is generated; and a signal processing unit that controls the compressed sensing signal generation unit and calculates a temperature or strain for each position of the sensing optical fiber from a signal output from the light detection unit.

It is provided a distributed sensing system, comprising: a light source, in particular Laser source, for providing a primary radiation; a primary radiation splitter arranged to receive the primary radiation at an input port and provide at least one injection radiation, a first reference radiation and a second reference radiation at at least three output ports; one or more optical fibres arrangeable to receive a respective fibre input radiation portion which is derived from the injection radiation; a light combining system configured, in particular for every one of the one or more optical fibres, to receive backscatter light returned from the one or more optical fibres, or light derived from the backscatter light, to receive the first reference radiation or light derived from the first reference radiation, and in particular to receive the second reference radiation or light derived from the second reference radiation, as light combining system radiation inputs and provide one or more light combining system radiation outputs based on the light combining system radiation inputs; a detection system configured to detect the one or more light combining system radiation outputs, thereby providing coherent detection.

A method for iteratively generating a matrix of base elements that includes forming at least one base matrix, applying modification operators iteratively, which are able to transform the base matrix or any matrix arising therefrom into a modified matrix, applying expansion operators iteratively, which form a larger matrix from a plurality of optionally modified smaller matrices from the preceding iteration by copying, rotation or reflection by virtue of parts of the larger matrix being filled with the optionally modified smaller matrices, performing virtual experiments within the scope of which the properties of a created matrix are examined by systematic creation of values deliberately containing errors from which an error signal is derivable, and in order to create a complex matrix, forming all permutations of next larger matrices by applying expansion operators and then evaluating by means of virtual experiments, the next larger matrices selected with the smallest error signals, and then forming the next larger matrices successively therefrom by applying expansion operators and evaluating by means of virtual experiments until the error signal drops below a given limit.