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.