Abstract: Methods and apparatus are provided for optical polarization mode dispersion compensator (PMDC) feedback control for APol-DPSK signals. A feedback signal generator includes a delay-line-interferometer (DLI), with a differential delay line delay (D) different from one bit period (Tb). In an exemplary embodiment, the DLI delay is in the range of 0.5 Tb<D<1.0 Tb, or 1.0 Tb<D<1.5 Tb, preferably 0.85 Tb or 1.15 Tb. The DLI is coupled to a single-ended detector, whose output is amplified and bandpass filtered around the frequency of half the bit rate. The filtered signal is then applied to an RF power detector to generate the PMDC feedback signal. Generation of the PMDC feedback signal in accordance with the present invention is insensitive to any alignment of the state of polarization (SOP) of the received APol-DPSK signal with the principal state of polarization (PSP) of the transmission link. As a result, there is no need for a polarization scrambler at the transmitter.

Abstract: An electromotor including a rotor rotatably running on bearings on a rotor shaft and a stator surrounding the rotor. The stator has a short-circuit body and a winding which can be impinged by current. The short-circuit body receives at least partly the medium line(s).

Abstract: Methods and apparatus are provided for optical polarization mode dispersion compensator (PMDC) feedback control for APol-DPSK signals. A feedback signal generator includes a delay-line-interferometer (DLI), with a differential delay line delay (D) different from one bit period (Tb). In an exemplary embodiment, the DLI delay is in the range of 0.5 Tb<D<1.0 Tb, or 1.0 Tb<D<1.5 Tb, preferably 0.85 Tb or 1.15 Tb. The DLI is coupled to a single-ended detector, whose output is amplified and bandpass filtered around the frequency of half the bit rate. The filtered signal is then applied to an RF power detector to generate the PMDC feedback signal. Generation of the PMDC feedback signal in accordance with the present invention is insensitive to any alignment of the state of polarization (SOP) of the received APol-DPSK signal with the principal state of polarization (PSP) of the transmission link. As a result, there is no need for a polarization scrambler at the transmitter.

Abstract: A light emitting device for a drive of medical instruments and/or hand pieces contains a carrier device consisting of at least one first layer and at least one second layer; and a luminous diode arranged on a surface of the carrier device pointing in a direction of light emission; the at least one first layer of the carrier device containing a conductive layer for power supply to the luminous diode; and the at least one second layer of the carrier device containing a thermal abstraction layer for carrying off the radiated heat of the luminous diode.

Abstract: The invention refers to an electromotor. This consists of a rotor rotatably running on bearings on a rotor shaft and a stator surrounding the rotor. The stator has a short-circuit body and a winding which can be impinged by current. The short-circuit body receives at least partly the medium line(s).

Abstract: The present invention includes apparatus and method of a variable step size dithering control algorithm for polarization mode dispersion controllers (PMDCs). The dithering step size of the PCs is adjusted according to the feedback signal including degree of polarization (DOP).

Abstract: The invention relates to a device for controlling an exhaust gas stream, in particular of an internal combustion engine in a passenger vehicle. Said device comprises a housing that can be traversed by exhaust gas (1) and a first displaceable actuating element (5) that is supported on the housing (1). The exhaust gas stream can be selectively guided into a first exhaust gas conduit (3) and/or a second exhaust gas conduit (4) by the displacement of the first actuating element (5). A second actuating element (15) is provided on the housing (1), said actuating element controlling a variable of thee exhaust gas stream.

Abstract: The invention relates to an exhaust gas heat exchanger (2), especially for motor vehicles, comprising a main flow path and a secondary flow path (bypass) for the exhaust gas. Said heat exchanger comprises a valve device (3) which is used to control the exhaust gas flow and can be actuated by a servomotor (4) by means of a transmission device (8, 6), the valve device (3) comprising a valve closing member fixed to a valve shaft (a). According to the invention, the valve shaft (a) can be loaded by a torsion spring (5) which can be supported on the valve shaft and on the valve device (3, 3a).

Abstract: Raman amplification is used in optical transmission systems, devices and/or components way of for applying Raman amplification avoiding or suppressing detrimental and hence undesirable non-linear effects is provided. Raman amplification in an optical device is provided by firstly determining a pump power (3) necessary for providing Raman amplification and then by providing a low spectral power density by pumping the optical device with pump power (3) at a relatively broad pump power spectrum and preferably a low spectral pump power amplitude such that the total output pump power (3) remains sufficiently high. The pump power (3) is optically attenuated prior to being coupled to the optical device.

Abstract: Wavelength control and stabilization of a laser is achieved by a practical, inexpensive, and accurate technique adapted for most optical transmission system applications by a method involving a laser characterization phase and a laser wavelength control and stabilization phase. This technique is applicable to both single mode lasers and multimode lasers. It is especially useful in those applications where the desired laser output power can vary over a wide range, including relatively low power above the lasing threshold.

Abstract: The present invention includes apparatus and method of a variable step size dithering control algorithm for polarization mode dispersion controllers (PMDCs). The dithering step size of the PCs is adjusted according to the feedback signal including degree of polarization (DOP).

Abstract: The dependency of intensity noise is used to determine the wavelength difference between a laser diode gain peak and a reflection peak of a fiber grating in a fiber grating type laser diode. Monitoring and determining the relative noise intensity of such a laser enables the control of the laser diode or the fiber grating such that the intensity noise is as low as possible. Such an approach enables the use of a fiber grating type laser diode as Raman pumps in high-speed transmission systems where low intensity noise is a requirement, especially when the Raman pump power propagates in the same direction as the transmission signals (known as Raman co-pumps).

Abstract: Wavelength control and stabilization of a laser is achieved by a practical, inexpensive, and accurate technique adapted for most optical transmission system applications by a method involving a laser characterization phase and a laser wavelength control and stabilization phase. This technique is applicable to both single mode lasers and multimode lasers. It is especially useful in those applications where the desired laser output power can vary over a wide range, including relatively low power above the lasing threshold.

Abstract: The dependency of intensity noise is used to determine the wavelength difference between a laser diode gain peak and a reflection peak of a fiber grating in a fiber grating type laser diode. Monitoring and determining the relative noise intensity of such a laser enables the control of the laser diode or the fiber grating such that the intensity noise is as low as possible. Such an approach enables the use of a fiber grating type laser diode as Raman pumps in high-speed transmission systems where low intensity noise is a requirement, especially when the Raman pump power propagates in the same direction as the transmission signals (known as Raman co-pumps).

Abstract: Raman amplification is used in optical transmission systems, devices and/or components. An object of the invention is to provide a new and improved way of proceeding for applying Raman amplification avoiding or suppressing detrimental and hence undesirable non-linear effects when applying Raman amplification to respective optical devices. The invention proposes to apply Raman amplification in an optical device by firstly determining a pump power (3) necessary for providing Raman amplification and then by providing a low spectral power density by pumping the optical device with pump power (3) at a relatively broad pump power spectrum and preferably a low spectral pump power amplitude such that the total output pump power (3) remains sufficiently high.

Abstract: In an optically amplified wavelength division multiplexed (WDM) system having a WDM signal comprising a plurality of optical channels, the per-channel gain of the optical channels is kept relatively constant despite changes in input power at the optical amplifier, such as when individual optical channels of the WDM signal are added and dropped. More specifically, gain of an optical amplifier is controlled by controlling the amount of pump power supplied to the optical amplifier as a function of changes in input power which are measured in a feed-forward monitoring path. The amount of pump power for effecting gain control is adjusted according to a scaled relationship to the measured input power of the optical amplifier. By controlling the pump power directly in response to changes in input power, gain of the optical amplifier can be controlled within a sub-microsecond time scale from the time that a change in input power is detected.

Abstract: An apparatus and method are described for controlling response to power transients in an optically amplified wavelength division multiplexed (WDM) network when WDM optical channels are added and dropped, during network reconfigurations, during failure events, and so on. In one embodiment, a variable bandwidth filter circuit operates at a first prescribed bandwidth during a first time period &tgr;0 to detect a change in signal power (i.e., power transient) caused by a transient event, and operates at a second prescribed bandwidth that is less than the first prescribed bandwidth after the first period of time elapses, e.g., &tgr;0+&Dgr;&tgr;, to substantially suppress low level signal variations, such as remnants of the power transient. In this way, the power transient related to the actual transient event will be preserved to trigger control circuitry, e.g.

Abstract: The invention relates to a method and an optical transmission system for compensation of dispersion in optical transmission lines in which dispersion compensation fibers are applied, with the dispersion compensation fibers being arranged at the beginning as well as at the end of the line segments of the optical fibers forming the transmission line. The signal distortions due to non-linear effects are reduced by making use of the recognition that non-linearities should only occur at as small as possible an accumulated dispersion. This is obtained by an unequal division of the dispersion compensation fiber applied for the compensation of the dispersion of the optical fiber, with the part of the dispersion compensation fiber attached at the beginning of a line segment being directly connected to the optical fiber and having an accumulated dispersion which is smaller as to amount than the accumulated dispersion of the part of the dispersion compensation fiber attached at the end of the optical fiber.

Abstract: A process for controlling the operation of a textile draw frame wherein a plurality of fiber slivers are fed to the draw frame at a predetermined desired delivery speed includes monitoring the presence of individual fiber slivers delivered to the draw frame and decreasing the delivery speed of the draw frame if any of the monitored fiber slivers is indicated as missing from being fed to the draw frame. The process includes subsequently increasing the delivery speed of the draw frame if the respective missing fiber slivers are again indicated as being fed to the draw frame. The invention also includes a draw frame including apparatus for carrying out the controlling process.

Abstract: A plurality of spindles of a textile machine are all mechanically interconnected and individually grouped, the individual groups of the spindles are driven by respective polyphase electric motors having respective feed lines all connected in parallel to the output lines of a polyphase electric power supply. Either the current or the voltage of the supply is maintained generally constant independent of load and a characteristic of the electricity in the feed lines of only one of the motors is monitored in the constant-current system or in the output lines of the supply in the constant-voltage system. An alarm, for example an optical or acoustic signal or just an indication on a display or printout, is generated when the characteristic of the electricity in any one of the monitored lines varies substantially from that of the other monitored lines.