Thorlabs Gmbh

Tektronix Munich

Egbert Krause

Adalbert Bandemer

Jens Peupelmann

Alex Cable

John Joseph Taranto

Stefan Michael Friedrich Baumhackl

Tobias Böhme

A positioning system, including: a first plate; a second plate coupled to the first plate and pivotable about an axis; a pair of voice coil actuators configured to rotate the second plate about this axis; and a processor configured to drive currents to the pair of voice coil actuators; wherein the pair of voice coil actuators comprises a first and second magnet structures mounted on the first plate at equal and opposite distance from the axis, and a first and second coils mounted on the second plate and positioned such that the respective first and second magnet structures move in and out of the first and second coils when the second plate rotates about the axis; wherein each of the first and second magnet structures substantially conforms to an arc having a center at the axis and a radius equal to the distance of the magnet structure from the axis.

Voice coil actuator for angular movements

A Shack Hartmann ('SH') wavefront sensor comprising an optical device, such as a wave front dissector including a lenslet array, for transmitting, dissecting and focusing an incoming optical wave, an optical system, including, for example, an optical sensor, for receiving the transmitted incoming optical wave, and a removable kinematic mount for repeatable precision mounting of the optical device to the optical system.

Shack Hartman sensor with removable lenslet array

A fiber polarimeter has one or more oblique fiber Bragg gratings disposed one behind the other in a fiber. The fiber Bragg gratings couple out portions of a light wave input to the fiber depending on its polarization. For more than one fiber Bragg grating a wave plate is disposed in the fiber between consecutive fiber Bragg gratings. The portions of the light wave from the fiber Bragg grating(s) are detected to produce measurement data that is used to calculate four Stokes parameters for determining polarization, degree of polarization and/or power of the light wave.

Fiber polarimeter, the use thereof, as well as polarimetric method

It is possible to improve the manner in which the chromatic dispersion of a sample () is determined. To this end, the sample () is irradiated in an interferometer (), with the light of a radiation source (). A downstream polarimeter () measures both the power changes and the polarization changes of the interference radiation. In the downstream evaluation unit () the wavelength-dependent chromatic dispersion can be determined.

Interferometric-based device and method for determining chromatic dispersion of optical components using a polarimeter

A PMD emulation, measurement and compensation device is based upon an emulation device having a piece of fiber having a fixed differential group delay (DGD) and another short piece of fiber (or double refracting crystal) having a variable differential group delay (T-DGD). The two pieces of fiber are coupled with a non-zero torsional angle between their respective double refractive axes, preferably 45&#xb0;. A fiber squeezer/stretcher is used to provide the variable DGD for the short piece of fiber. Various serial couplings of DGD and T-DGD fiber may be added to provide greater control and accuracy, with the torsional angles preferably alternating. Such an emulation device may be incorporated into a measurement device to measure the PMD-related distortion of an optical signal. Further the measurement device may be used in a PMD compensator where an emulation device in series with the optical signal path is controlled until the measured PMD in the PMD-related distorted optical signal is minimized.

PMD emulation, measurement and compensation device

Highly accurate calibration of a polarimeter of the type having at least four detectors involves using four known states of polarisation of an input light signal (calibration polarisations) and at least one further state of polarisation. All input states of polarisation to the polarimeter have unity normalised power of the light signal and unity degree of polarisation. A Stokes matrix for the four calibration polarisations is generated with at least one variable correction parameter, and a correction matrix is determined from the Stokes matrix and a corresponding detector current matrix measured by the polarimeter. An optimisation criterion that is a function of the degrees of polarisation for the states of polarisation as measured by the polarimeter is generated. The correction parameter is varied iteratively to minimise the optimisation criterion so that the polarimeter is calibrated to produce unity power and degree of polarisation for any input state of polarisation.

Highly accurate calibration of polarimeters

The invention relates to a device for detecting the PMD of optoelectronic transmission lines. The inventive device is characterized in that it comprises a narrow-band, tunable laser, whose illumination is superimposed with the illumination of the transmission line to be analyzed and an optoelectronic heterodyne receiver which receives the superimposed signal.

Device for detecting the PMD of optoelectronic transmission lines

The invention describes a system to compensate distortions caused by polarization modulation dispersion (PMD) in optical transmission systems and particularly transmission fibers, with a measuring device for distortions caused by PMD, an emulation unit for adjustable PMD values, a polarization transformation element, which adjusts the polarization of the signals coming from a transmission system to the PMD emulation unit, an analyzer and control unit, connected to the output signal of the measuring device, which unit controls the emulation unit and the polarization adjuster element. The invention is distinguished in that the emulation unit has a PMD emulator, which emulates PMD of second or higher order and matches PMD of a real transmission fiber as exactly as possible, and that the one or more PMD emulators compensate one or more transmission channels, and/or that the measuring device optically detects the PMD directly or by way of the detection of polarization conditions.

Growing community of inventors

Burgstaedt, Germany

Egbert Krause