Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A system and method including polarization modulation of supervisory signals for reducing interference with data signals in a wavelength division multiplexed optical communication system. At least one supervisory signal for monitoring a transmission path and/or elements coupled to the transmission path is fast polarization modulated and launched with data signals onto the path. Polarization modulating of the supervisory signal reduces impact of the supervisory signal on the data signals and improves system performance.

Abstract: A system and method including polarization modulation of supervisory signals for reducing interference with data signals in a wavelength division multiplexed optical communication system. At least one supervisory signal for monitoring a transmission path and/or elements coupled to the transmission path is fast polarization modulated and launched with data signals onto the path. Polarization modulating of the supervisory signal reduces impact of the supervisory signal on the data signals and improves system performance.

Abstract: A driver warning system automatically detects the existence of in-the-road, passable obstructions and provides timely notification to a driver in proximity of such an in-the-road, passable obstruction prior to it being encountered with sufficient warning time for the driver to avoid the in-the-road, passable obstruction. To detect in-the-road, passable obstructions, the warning unit of a driver whose vehicle hits an in-the-road, passable obstruction will automatically generate a signal that is indicative of the existence of the in-the-road, passable obstruction and its location. This signal may be transmitted to a server, which contains a database of located obstructions. The collected information about the detected in-the-road, passable obstructions are provided to various warning units, so that they, knowing the driver location, e.g.

Abstract: A driver warning system automatically detects the existence of in-the-road, passable obstructions and provides timely notification to a driver in proximity of such an in-the-road, passable obstruction prior to it being encountered with sufficient warning time for the driver to avoid the in-the-road, passable obstruction. To detect in-the-road, passable obstructions, the warning unit of a driver whose vehicle hits an in-the-road, passable obstruction will automatically generate a signal that is indicative of the existence of the in-the-road, passable obstruction and its location. This signal may be transmitted to a server, which contains a database of located obstructions. The collected information about the detected in-the-road, passable obstructions are provided to various warning units, so that they, knowing the driver location, e.g.

Abstract: An orthogonal heterodyne in-band optical signal-to-noise-ratio (OSNR) monitoring method and apparatus that use the polarization characteristics of two narrow bandwidth filtered optical spectral components which is not only insensitive to the effects of polarization mode dispersion (PMD) and inter-channel cross-phase modulation (XPM) induced nonlinear polarization scattering, but also independent of bit rate and modulation format. The monitoring method is demonstrated for both linear and nonlinear systems.

Abstract: A method for reducing deleterious effects of higher-order polarization mode dispersion (PMD) on the quality of data transmission in a long-haul optical communication system. An optical bandpass filter (OBF) designed for spectral bandwidth reduction of a received data-modulated optical signal is placed at the receiver end of the communication system next to a first-order PMD compensator. The OBF may be, e.g., a Mach-Zehnder filter having a bandwidth approximately equal to a modulation frequency of the optical signal. A center frequency of the OBF may be detuned from that of the optical signal. Using the OBF at the receiver may decrease a number of optical bit errors associated with the effects of higher-order PMD.

Abstract: A polarization mode dispersion (PMD) emulator may include one or more modular “cells” that emulate PMD. Each of the cells may include optical delay and phase modulation components. The optical delay and/or the phase modulation components may be adjusted to account for differences in PMD and two or more of the cells may be combined to further adjust the overall PMD of the apparatus. Similarly, a PMD compensator may include one or more modular “cells” that compensate for PMD, with each of the cells including optical delay and phase modulation components. The optical delay and/or the phase modulation components may be adjusted to compensate for various PMD values and two or more of the cells may be combined to further adjust the overall PMD compensation of the apparatus. The PMD compensator apparatus may be used to compensate for PMD in wideband applications, such as wavelength division multiplexed (WDM) systems.

Abstract: The invention relates to a method and a device for wavelength stabilizing for multichannel optical transmission systems. An optical multiplexer is used directly for the generation of the optical total signal. This makes possible a simple electronic regulation of wavelengths of the optical carrier signals through analysis of the amplitude values of low-frequency signals, which modulate the optical carrier signals by means of amplitude modulation.

Abstract: The invention relates to a method and a device for wavelength stabilizing for multichannel optical transmission systems. An optical multiplexer is used directly for the generation of the optical total signal. This makes possible a simple electronic regulation of wavelengths of the optical carrier signals through analysis of the amplitude values of low-frequency signals, which modulate the optical carrier signals by means of amplitude modulation.