Abstract: A method in a transceiver apparatus for monitoring an optical link over which one or more data signals are to be transmitted comprises time interleaving a test signal with an auxiliary management and control channel, AMCC, signal to form a time-interleaved signal. The time-interleaved signal is transmitted with one or more downstream data signals over the optical link. A backscattered test signal is received to monitor the optical link.

Abstract: A method in a transceiver apparatus for monitoring an optical link over which one or more data signals are to be transmitted comprises time interleaving a test signal with an auxiliary management and control channel, AMCC, signal to form a time-interleaved signal. The time-interleaved signal is transmitted with one or more downstream data signals over the optical link. A backscattered test signal is received to monitor the optical link.

Abstract: A method for monitoring an optical fiber link comprises generating a monitoring signal used for monitoring the optical fiber link, combining the generated monitoring signal with a data signal to be transmitted over the optical fiber link, detecting backscattering of the monitoring signal from the optical fiber link, detecting a change in characteristic of the detected backscattered monitoring signal, and determining, from the detected change in characteristic, at least one location along the optical fiber link where the monitoring signal is modified, and signal loss at this location.

Abstract: The invention relates to a device and a method performed by the device of monitoring an optical fibre link. The method provided for monitoring an optical fibre link comprises generating a monitoring signal used for monitoring the optical fibre link, combining the generated monitoring signal with a data signal to be transmitted over the optical fibre link, detecting backscattering of the monitoring signal from the optical fibre link, comparing the detected backscattered monitoring signal with an estimated monitoring signal backscattered along the optical fibre link, and determining, based on the comparison, at least one location along the optical fibre link where the monitoring signal is backscattered, and signal loss caused by the backscattering.

Abstract: A method for monitoring an optical fibre link comprises generating a monitoring signal used for monitoring the optical fibre link, combining the generated monitoring signal with a data signal to be transmitted over the optical fibre link, detecting backscattering of the monitoring signal from the optical fibre link, detecting a change in characteristic of the detected backscattered monitoring signal, and determining, from the detected change in characteristic, at least one location along the optical fibre link where the monitoring signal is modified, and signal loss at this location.

Abstract: Methods, optical transmitters and a system of optical transmitters for transmitting data over and monitoring a fibre cable. A method performed by an optical transmitter for transmitting data over and monitoring of a fibre cable comprises generating at least a first optical carrier and a second optical carrier at a same optical frequency, generating an electromagnetic monitoring signal, modulating the first optical carrier with the generated electromagnetic monitoring data signal to create an optical monitoring signal, and modulating the second optical carrier with a generated electromagnetic data signal to create an optical data signal. The method further comprises combining the optical monitoring signal and the optical data signal in orthogonal polarization modes, transmitting the combined optical monitoring signal and the optical data signal over the fibre cable to be monitored, and monitoring the fibre cable by detecting the optical monitoring signal being backscattered from the fibre cable.

Abstract: Methods, optical transmitters and a system of optical transmitters for transmitting data over and monitoring a fiber cable. A method performed by an optical transmitter for transmitting data over and monitoring of a fiber cable comprises generating at least a first optical carrier and a second optical carrier at a same optical frequency, generating an electromagnetic monitoring signal, modulating the first optical carrier with the generated electromagnetic monitoring data signal to create an optical monitoring signal, and modulating the second optical carrier with a generated electromagnetic data signal to create an optical data signal. The method further comprises combining the optical monitoring signal and the optical data signal in orthogonal polarization modes, transmitting the combined optical monitoring signal and the optical data signal over the fiber cable to be monitored, and monitoring the fiber cable by detecting the optical monitoring signal being backscattered from the fiber cable.

Abstract: The invention relates to a device and a method performed by the device of monitoring an optical fibre link. The method provided for monitoring an optical fibre link comprises generating a monitoring signal used for monitoring the optical fibre link, combining the generated monitoring signal with a data signal to be transmitted over the optical fibre link, detecting backscattering of the monitoring signal from the optical fibre link, comparing the detected backscattered monitoring signal with an estimated monitoring signal backscattered along the optical fibre link, and determining, based on the comparison, at least one location along the optical fibre link where the monitoring signal is backscattered, and signal loss caused by the backscattering.

Abstract: The present invention relates to an optical amplifier arrangement and a method of amplifying an optical signal. The optical amplifier arrangement (20) comprises an optical dividing device (21) arranged to divide an optical input pulse into a plurality of non-overlapping pulses forming a pulse train, an optical amplifier (22) arranged to amplify the pulse train, and an optical aligning display (23) arranged to temporally align the plurality of amplified pulses in the amplified pulse train into a single output pulse having the same temporal width as the input pulse.

Abstract: The present invention relates to a device for monitoring an optical fiber comprising a photo-sensitive device arranged to produce an electric pulse from an optical pulse injected at a first node of the optical fiber, a delay element and a first optical circulator arranged to delay the optical pulse injected at the first node of the optical fiber. Further, the device comprises an optical amplifier arrangement arranged to receive the optical pulse at its input and the produced electric pulse as an operating signal, for producing an amplified optical pulse. Moreover, the device comprises a second optical circulator arranged to receive the amplified optical pulse at a first port and output the amplified optical pulse at a second port connected to a second node of the optical fiber, and to receive an optical signal reflected back from the optical fiber at the second port and outputting the reflected optical signal at a third port.

Abstract: A system for supervision of a passive optical network includes an OTDR device, generating N+1 OTDR signals of wavelengths ?U-?N, and transmitting the signals towards ONUs. The system includes a splitter having N output branches. An input of the splitter is connected to the output of the OTDR device and the output branches of the splitter are indirectly connected to the ONUs. The splitter splits the OTDR signals and forwards them towards the ONUs. The system includes a wavelength isolator having inputs connected to the splitter output branches. The wavelength isolator isolates, on individual inputs, one predetermined wavelength of the received OTDR signals per individual input, where two inputs of the wavelength isolator do not isolate the same wavelength, and forwards, from each of the inputs of the wavelength isolator, the OTDR signals to associated outputs towards the ONUs connected to the wavelength isolator by individual fiber links.

Abstract: The present invention relates to an optical amplifier arrangement and a method of amplifying an optical signal.

Abstract: The present invention relates to a device for monitoring an optical fibre comprising a photo-sensitive device arranged to produce an electric pulse from an optical pulse injected at a first node of the optical fibre, a delay element and a first optical circulator arranged to delay the optical pulse injected at the first node of the optical fibre. Further, the device comprises an optical amplifier arrangement arranged to receive the optical pulse at its input and the produced electric pulse as an operating signal, for producing an amplified optical pulse. Moreover, the device comprises a second optical circulator arranged to receive the amplified optical pulse at a first port and output the amplified optical pulse at a second port connected to a second node of the optical fibre, and to receive an optical signal reflected back from the optical fibre at the second port and outputting the reflected optical signal at a third port.

Abstract: A system for supervision of a passive optical network includes an OTDR device, generating N+1 OTDR signals of wavelengths ?U-?N, and transmitting the signals towards ONUs. The system includes a splitter having N output branches. An input of the splitter is connected to the output of the OTDR device and the output branches of the splitter are indirectly connected to the ONUs. The splitter splits the OTDR signals and forwards them towards the ONUs. The system includes a wavelength isolator having inputs connected to the splitter output branches. The wavelength isolator isolates, on individual inputs, one predetermined wavelength of the received OTDR signals per individual input, where two inputs of the wavelength isolator do not isolate the same wavelength, and forwards, from each of the inputs of the wavelength isolator, the OTDR signals to associated outputs towards the ONUs connected to the wavelength isolator by individual fibre links.

Abstract: An FSO transceiver (4) comprising a body (6), at least one lens (9) fixed to the body in a first position (C) and means for attaching a connector (11) for an optical fiber (3) at a second position (B) at a predefined distance (Zbc) to the lens, the lens being adapted to converge rays (8) of light sent to the FSO transceiver via free space into the optical fiber. The means for attaching the connector is a temperature compensation device (10) having an expansion coefficient being higher than an expansion coefficient of the body and that the temperature compensation device is fixed to the body in a third position (A) and has a free end which allows the temperature compensation device to expand or contract according to temperature changes, and that the second position is positioned between the third position and the first position.

Abstract: In an optical transmission system including a transmitter Tx and a receiver Rx connected via a fiber link F, where the receiver Rx is adapted to utilize Forward Error Correction (FEC) on received signals, a polarization scrambler is provided at the transmitter Tx to scramble the polarization state of a transmitted signal, a polarization delay line is provided at the receiver Rx for controlling the polarization mode dispersion induced distortion of a received signal, a feedback unit is provided at the receiver Rx for providing a feedback signal based on at least part of the received signal, and at least one polarization controller interconnects the fiber link F and the polarization delay line. The polarization controller is operable based on the feedback signal to mitigate the polarization mode dispersion of the signal.

Abstract: An FSO transceiver (4) comprising a body (6), at least one lens (9) fixed to the body in a first position (C) and means for attaching a connector (11) for an optical fiber (3) at a second position (B) at a predefined distance (Zbc) to the lens, the lens being adapted to converge rays (8) of light sent to the FSO transceiver via free space into the optical fiber. The means for attaching the connector is a temperature compensation device (10) having an expansion coefficient being higher than an expansion coefficient of the body and that the temperature compensation device is fixed to the body in a third position (A) and has a free end which allows the temperature compensation device to expand or contract according to temperature changes, and that the second position is positioned between the third position and the first position.

Abstract: In an optical transmission system including a transmitter Tx and a receiver Rx connected via a fiber link F, where the receiver Rx is adapted to utilize Forward Error Correction (FEC) on received signals, a polarization scrambler is provided at the transmitter Tx to scramble the polarization state of a transmitted signal, a polarization delay line is provided at the receiver Rx for controlling the polarization mode dispersion induced distortion of a received signal, a feedback unit is provided at the receiver Rx for providing a feedback signal based on at least part of the received signal, and at least one polarization controller interconnects the fiber link F and the polarization delay line. The power controller is operable based on the feedback signal to mitigate the polarization mode dispersion of the signal.

Abstract: Method and apparatus for compensating for first-order Polarization Mode Dispersion in an optical transmission system. An apparatus has a polarization controller for transforming polarization components of an optical signal carried by the optical fiber into orthogonal polarization states, a variable delay line for introducing a variable differential time delay between the polarization states and for producing an output optical signal that is compensated for PMD in the optical fiber, and a feedback unit for adjusting the polarization controller and the variable delay line to compensate for variations in the PMD of the optical fiber, the feedback unit including apparatus for generating a plurality of independent control signals to independently control actuators of the polarization controller and the variable delay line. The invention provides for a reduction in response time of the actuators and a reduction in complexity of an algorithm used to control the apparatus.

Abstract: Method and apparatus for compensating for first-order Polarization Mode Dispersion in an optical transmission system. An apparatus has a polarization controller for transforming polarization components of an optical signal carried by the optical fiber into orthogonal polarization states, a variable delay line for introducing a variable differential time delay between the polarization states and for producing an output optical signal that is compensated for PMD in the optical fiber, and a feedback unit for adjusting the polarization controller and the variable delay line to compensate for variations in the PMD of the optical fiber, the feedback unit including apparatus for generating a plurality of independent control signals to independently control actuators of the polarization controller and the variable delay line. The invention provides for a reduction in response time of the actuators and a reduction in complexity of an algorithm used to control the apparatus.