Abstract: A method for determining the position of an irregularity in an optical transmission fiber using an optical time domain reflectometer, the method comprising the steps of emitting a succession of sampling light pulses into the optical transmission fiber, detecting reflected light pulses resulting from the reflection of the sampling light pulses at the irregularity in the optical transmission fiber and generating corresponding time-dependent detection signals, wherein different delays are associated with detection signals corresponding to different sampling light pulses, obtaining a combined signal from the detection signals, and analyzing the combined signal for determining the position of the irregularity in the optical transmission fiber with respect to the optical time domain reflectometer, wherein the combined signal corresponds to a super-position of the detection signals.

Abstract: A system (10) for detecting a level of dirtiness of a filter mat (20) of an airflow cooling system for telecommunications equipment, the system (10) comprising a detector (12) for detecting fluorescent or reflected light backscattered at at least one part in (22) of the filter mat (20) comprising or treated with a fluorescent or reflective material, wherein the detector (12) comprises a light source (12a) for illuminating said at least one part (22) of the filter mat (20) with sampling light, and a photosensor (12b) for detecting fluorescent or reflected light backscattered at said at least one part (22) of the filter mat (20) caused by the illumination thereof with sampling light, wherein the system (10) is configured for inferring the level of dirtiness of the filter mat (20) from the amount of detected fluorescent or reflected light.

Abstract: A Raman pumping device (10) for amplifying a data optical signal in a fiber optic transmission system, comprising first and second ports (12a, 12b) through which the data optical signal may respectively enter and exit the Raman pumping device (10), a Raman pump source (14) for generating a Raman pump signal, and at least one combiner (16) for combining the Raman pump signal with the data optical signal. The Raman pumping device (10) allows for selectively combining the Raman pump signal generated by the same Raman pump source (14), or at least parts of the same Raman pump source (14) codirectionally or counterdirectionally with the data optical signal.

Abstract: Disclosed is a method of Controlling a gain of an optical amplifier comprising a gain medium and at least one pumping device. The method comprises the following steps: determining or predicting a change of input signal power to the amplifier, changing the pump power from an initial pump power level to a new pump power level at a first time instant, the initial pump power level being the pump power level applied to the amplifier prior to the change in input signal power, setting the pump power to a second pump power level at a second time instant, wherein the pump power level is varied in an oscillatory manner for at least one period of time starting at a third time instant and ending at a fourth time instant, wherein said third time instant is identical with or later than said first time instant and said fourth time instant is identical with or earlier than said second time instant.

Abstract: A Raman pumping arrangement for amplifying a data optical signal (40) has a Raman pump (12) for generating a Raman pump signal (44;45), an optical supervisory channel receiver (14) for receiving an optical supervisory channel signal (42) an amplification fiber (15) arranged such that the data optical signal (40), the optical supervisory channel signal (42), and the Raman pump signal (44;45) are transmitted therethrough; and a control unit (13) configured for controlling the operation of the Raman pump (12); wherein the control unit (13) is configured for setting the Raman pump (12) in an operation mode or a start-up mode; wherein in the operation mode, the Raman pump (12) provides an operation pumping power (120), and wherein in the start-up mode, the Raman pump (12) provides a start-up pumping power (122).

Abstract: A Raman pumping arrangement for amplifying a data optical signal (40) has a Raman pump (12) for generating a Raman pump signal (44;45), an optical supervisory channel receiver (14) for receiving an optical supervisory channel signal (42) an amplification fiber (15) arranged such that the data optical signal (40), the optical supervisory channel signal (42), and the Raman pump signal (44;45) are transmitted therethrough; and a control unit (13) configured for controlling the operation of the Raman pump (12); wherein the control unit (13) is configured for setting the Raman pump (12) in an operation mode or a start-up mode; wherein in the operation mode, the Raman pump (12) provides an operation pumping power (120), and wherein in the start-up mode, the Raman pump (12) provides a start-up pumping power (122).

Abstract: It is provided an apparatus, comprising a box configured to conduct an optical fiber from an exterior to an interior of the box; at least one of a mounting means adapted to mount a connecting means to which the optical fiber may be connected and a guiding means adapted to guide the optical fiber, wherein the at least one of the mounting means and the guiding means is arranged in the interior of the box; a detecting means arranged in the interior of the box adapted to detect a first signal from the interior of the box, wherein the first signal is at least one of a light and a smoke; wherein the interior of the box is substantially shielded from a second signal from an exterior of the box, and the detecting means is suitable to detect the second signal in a same manner as the first signal.

Abstract: An optical network is suggested, comprising a first set of optical fibers, a multimode multiplexer, a multimode amplifier, a multimode demultiplexer, and a second set of optical fibers, wherein the first set of optical fibers is connected via the multimode multiplexer to the multimode amplifier and wherein the multimode amplifier is connected via the multimode demultiplexer to the second set of optical fibers. Accordingly, an optical network element is provided.

Abstract: Disclosed is a method of Controlling a gain of an optical amplifier comprising a gain medium and at least one pumping device. The method comprises the following steps: determining or predicting a change of input signal power to the amplifier, changing the pump power from an initial pump power level to a new pump power level at a first time instant, the initial pump power level being the pump power level applied to the amplifier prior to the change in input signal power, setting the pump power to a second pump power level at a second time instant, wherein the pump power level is varied in an oscillatory manner for at least one period of time starting at a third time instant and ending at a fourth time instant, wherein said third time instant is identical with or later than said first time instant and said fourth time instant is identical with or earlier than said second time instant.

Abstract: A method and a device is provided driving an optical laser diode (710, 711) during operation in an optical communication network, by determining a laser transfer function (741, 742) during operation of the laser diode (710, 711) and providing a control signal (750, 749) for driving the laser diode (710, 711) according to the laser transfer function (741, 742). Further, a method for driving a first and a second optical laser diode during operation in an optical communication network is provided. Furthermore, an optical amplifier and a communication system is suggested.

Abstract: An optical network is suggested, comprising a first set of optical fibers, a multimode multiplexer, a multimode amplifier, a multimode demultiplexer, and a second set of optical fibers, wherein the first set of optical fibers is connected via the multimode multiplexer to the multimode amplifier and wherein the multimode amplifier is connected via the multimode demultiplexer to the second set of optical fibers. Accordingly, an optical network element is provided.

Abstract: An optical communication system, a method and a network device for an optical network are provided, wherein the device comprises a first port coupled with a first optical fiber link, a second port coupled with a second optical fiber link, the first port and the second port being configured to be coupled with respect to each other in case of a failure of the first optical fiber link or in case of a failure of the second optical fiber link.

Abstract: A method for operating an optical network element is provided, wherein based on a quality parameter a subsequent set of parameters is selected to operate the optical network element. Also, an according optical network element and a communication system comprising at least one such optical network element are suggested.

Abstract: A method and a device is provided driving an optical laser diode (710, 711) during operation in an optical communication network, by determining a laser transfer function (741, 742) during operation of the laser diode (710, 711) and providing a control signal (750, 749) for driving the laser diode (710, 711) according to the laser transfer function (741, 742). Further, a method for driving a first and a second optical laser diode during operation in an optical communication network is provided. Furthermore, an optical amplifier and a communication system is suggested.

Abstract: It is provided an apparatus, comprising a box configured to conduct an optical fiber from an exterior to an interior of the box; at least one of a mounting means adapted to mount a connecting means to which the optical fiber may be connected and a guiding means adapted to guide the optical fiber, wherein the at least one of the mounting means and the guiding means is arranged in the interior of the box; a detecting means arranged in the interior of the box adapted to detect a first signal from the interior of the box, wherein the first signal is at least one of a light and a smoke; wherein the interior of the box is substantially shielded from a second signal from an exterior of the box, and the detecting means is suitable to detect the second signal in a same manner as the first signal.

Abstract: A method for operating an optical network element is provided, wherein based on a quality parameter a subsequent set of parameters is selected to operate the optical network element. Also, an according optical network element and a communication system comprising at least one such optical network element are suggested.

Abstract: An optical network is suggested, comprising a first set of optical fibers, a multimode multiplexer, a multimode amplifier, a multimode demultiplexer, and a second set of optical fibers, wherein the first set of optical fibers is connected via the multimode multiplexer to the multimode amplifier and wherein the multimode amplifier is connected via the multimode demultiplexer to the second set of optical fibers. Accordingly, an optical network element is provided.

Abstract: A method for controlling a variation in gain in an optical amplifier stage and an optical amplifier. The optical amplifier stage includes a pumping device for providing pumping power and a control unit for determining a change in an input power of the optical amplifier. The method includes the steps of determining a change in an input power of the optical amplifier, adjusting a pumping power of the pumping device to a first power level for a predetermined period of time and adjusting the pumping power of the pumping device to a second power level. The second power level is able to drive the amplifier gain to a predetermined gain value after the change in the input power occurred.

Abstract: An optical amplifier with improved transient performance has two amplifier stages and a gain flattening filter-inserted between the amplifier stages. A control unit generates a pump control signal for a common pump source pumping both amplifier stages. The pump control signal has a feed-forward component and a feedback component. After a drop of channels the feed-forward control circuit is responsible for the transient performance and fast gain stabilization. The characteristic of the gain flattening filter is taken into account in calculating an optimum feed-forward control signal.

Abstract: A method removes signal interference in a passive optical network. The passive optical network includes an optical line terminal, a splitting unit coupled with the optical line terminal, an optical network unit coupled with the splitting unit, and an identification signal uniquely associated with the optical network unit. The method includes the steps of sending a first signal, detecting the first signal, comparing the detected first signal with an identification signal and decoupling the optical network unit from the splitting unit if the comparing step results in a mismatch.