Abstract: A wavelength shifter module and a method therein for tuning an OTDR signal to at least one pre-selected wavelength in a passive optical network (PON). The wavelength of the OTDR signal is shifted to a pre-selected wavelength to enable a remote node in the optical distribution network ODN of the PON to forward the OTDR signal to a specific drop section in the ODN. The invention also includes a remote node and a method in a remote node for receiving a wavelength shifted OTDR signal having a preselected wavelength and outputting the wavelength shifted OTDR signal to a specific drop section. Furthermore, the invention involves a method for determining the location of a fault section in a drop section.

Abstract: An optical device, OD, for partitioning a received signal and outputting the partitions via two outputs. An optical distribution network comprising at least two Optical Network Terminations, ONTs, the ONTs being connected to the CO by the fibre ring structure, wherein each ONT is connected to the fibre ring structure by means of a respective OD is provided. The OD has a first port, a second port and a third port, each port being operable as both an input and an output interface. The first and second ports are adapted to receive an input signal, to split the signal and to output a first respective portion of the received signal through the second or first port respectively and to output a respective second portion of the received signal through the third port, the first portion of the received signal being larger than the second portion of the received signal.

Abstract: Embodiments herein relate to a method in a network unit for monitoring a fiber line between a radio base station and a radio head in a Fiber to the Radio Head communications network. The Fiber to the Radio Head communications network comprises a ring architecture or a tree architecture of fiber, with Subcarrier Multiplexing, SCM, downstream transmissions and Wavelength Division Multiplexing, WDM, upstream transmissions. The monitoring comprises that the network unit detects an indication of a fault along the fiber line based on monitoring power. The network unit initiates, in response to detect the indication, an Optical x Domain Reflectometry, OxDR, measurement over the fiber line. Additionally, the network unit analyses a trace from the OxDR measurement for localizing the fault or for deciding that the indicated fault is not a fault along the fiber line.

Abstract: A Wavelength Adaptation Module and a method therein for adapting an Optical Time Domain Reflectometry, OTDR, signal for supervision of Optical Network Terminals, ONTs, in a Passive Optical Network, PON, are provided. The wavelength of the OTDR signal is adapted to have a pre-selected wavelength to enable a splitter in a remote node to forward the OTDR signal to a dedicated group of ONTs in the PON, thereby supervising the fiber links between the remote node and the dedicated group of ONTs. Likewise, a remote node and a method therein for receiving an OTDR signal having a pre-selected wavelength from the Wavelength Adaptation Module and for outputting the OTDR signal to a dedicated group of ONTs with regards to the pre-selected wavelength of the received OTDR signal are provided.

Abstract: Fault analysis of a Passive Optical Network comprising Optical Network Terminal(s) uses Optical Time Domain Reflectometry (OTDR). An OTDR measurement signal is supplied to a multistage splitter having a ratio 2:Nroot. At least one drop link which is connected to the multistage splitter comprises one or more sub-splitters which having a ratio 1:Nbranch. A new event location is determined based on the OTDR measurement signal by analyzing OTDR measurement data relating to the sub-splitter based on distance from the multistage splitter and to the sub-splitter. A fault magnitude is calculated for a given location by subtracting an event magnitude obtained from the new OTDR measurement from a reference OTDR measurement and taking into account the number of drop links connected to the last splitter stage and to the sub-splitter in the reference measurement and the new measurement, thereby enabling determination of position and severity of the fault locations.

Abstract: Methods and apparatuses for enabling supervision of fibers in an optical communication network, where a Central Office provides data signals to a Remote Node for distribution to Optical Network Terminals (ONTs). The Central Office generates and sends test signals of different monitoring wavelengths associated to predefined groups of said ONTs, to the Remote Node. The Remote Node routes each test signal to a corresponding associated group of ONTs according to the wavelength of the test signal. When receiving a back-scattered and back-reflected test signal caused by a faulty optical fiber, the Central Office is able to identify the faulty optical fiber based on the wavelength of the back-scattered and back-reflected signal.

Abstract: It is disclosed a remote node connectable to multiple feeder fibers from one or more central offices, COs, of a wavelength division multiplexing-based passive optical network, WDM-based PON. The remote node comprises one or more splitters each configured to receive a monitoring signal on a connected feeder fiber and to split the monitoring signal into split monitoring signals, wherein the monitoring signal uses one wavelength at a time out of a group of different wavelengths, and an arrayed waveguide grating, AWG, with output ports connectable to drop fibers. The AWG is configured to route the split monitoring signals to output ports of said AWG based on a currently used wavelength of said group of different wavelengths, for supervising drop fibers connected to the output ports. Also, a method for a remote node in the WDM-based PON, of routing a monitoring signal, is disclosed.

Abstract: A method performed by a transceiver for use in fiber network for sending and/or receiving signals. Transceiver includes SCM device; laser diode; Red-Blue Filter, RBF, having red, blue and common channels; PD; and Subcarrier Demultiplexing, SCDM, device. SCM device receives electromagnetic signals on at least two input ports, multiplexes electromagnetic signals and outputs signal to laser diode. Laser diode receives signal, converts signal to optical signals comprising plurality of subcarriers of different frequencies distributed in frequency around main optical carrier, and outputs subcarriers to red channel of RBF. RBF receives subcarriers and outputs to the fiber network via common channel. RBF receives subcarriers on common channel and filters out blue frequencies and outputs to photo diode. Photodiode receives the subcarriers having blue wavelengths, converts subcarriers into electromagnetic signal and outputs electromagnetic signal to SCDM device.

Abstract: An ONT and a method therein for maintenance and administration of the ONT are provided. The ONT is comprised in an Optical Distribution Network, ODN. The method comprises connecting 210 an OLT in the ODN to a maintenance unit comprised in the ONT when a first signal is received from the OLT instructing the ONT to enter a maintenance mode. The method comprises updating 220 existing maintenance and administration information in the maintenance unit, the maintenance and administration information relating to the operation of the ONT when receiving new maintenance and administration information from the OLT. The method comprises connecting 230 the OLT to a host which host is connected to the ONT when receiving, from the OLT, a second signal instructing the ONT to enter an operation mode, or after a predetermined period of time; and operating 240 the ONT in accordance with the updated maintenance and administration information in the maintenance unit.

Abstract: A method and arrangement in an Optical Network Terminal, ONT for monitoring the state of an Optical Distribution Network, ODN, in a Passive Optical Network, PON, is provided. The ONT receives an optical signal, from an Optical Line Terminal, OLT, having optical power, Po,sat, causing a Semiconductor Optical Amplifier, SOA, comprised in the ONU, to reach a saturated state. One or more parameters are measured. The parameters relates to the power provided from a power source to the SOA during a predefined time period, where the SOA is in a saturated state during the predefined time period. Information relating to the measured parameters are provided to the OLT and thereby enabling the OLT to compare the current state of the ODN to a previously measured reference state of the ODN.

Abstract: A Passive Optical Network, PON, comprising an Optical Line Termination, OLT, connected to one or more Optical Network Terminals, ONT, over an Optical Distribution Network, ODN, is monitored by a monitoring device. The monitoring device comprises an Optical Frequency Domain Reflectometer, OFDR, and is arranged to monitor the optical power received by the OLT and the ONTs of the PON, and to perform transceiver analysis of the OLT and the ONTs, combined with an OFDR analysis of the ODN, based on the monitored optical power violating a threshold.

Abstract: A method performed by a transceiver for use in fibre network for sending and/or receiving signals. Transceiver includes SCM device; laser diode; Red-Blue Filter, RBF, having red, blue and common channels; PD; and Subcarrier Demultiplexing, SCDM, device. SCM device receives electromagnetic signals on at least two input ports, multiplexes electromagnetic signals and outputs signal to laser diode. Laser diode receives signal, converts signal to optical signals comprising plurality of subcarriers of different frequencies distributed in frequency around main optical carrier, and outputs subcarriers to red channel of RBF. RBF receives subcarriers and outputs to the fibre network via common channel. RBF receives subcarriers on common channel and filters out blue frequencies and outputs to photo diode. Photodiode receives the subcarriers having blue wavelengths, converts subcarriers into electromagnetic signal and outputs electromagnetic signal to SCDM device.

Abstract: An arrangement at a Remote Node, a Remote Node, a Central Office, a WDM-PON and a method in an arrangement at a Remote Node, and a method in a Central Office are provided for supervision of the WDM-PON. The arrangement comprises at least one filter connected to the feeder fiber links and adapted to separate a data signal and an original OTDR signal received on either of the feeder fiber links. Further, the arrangement comprises a first splitter adapted to receive, from the at least one filter, the original OTDR signal, to split the original OTDR signal into a plurality of OTDR sub-signals and to output, to an N*M AWG, the plurality of OTDR sub-signals. The at least one filter is further adapted to output the original OTDR signal to the first splitter and to output the data signal to the AWG, thereby enabling supervision of the WDM-PON.

Abstract: An arrangement in a node in a WDM-PON and a method therein for supervision of the WDM-PON are provided. The arrangement comprises X splitters of splitting ratio 1:Y, each splitter having one input and Y outputs such that X*Y equals N, wherein X, Y, N are integers. The one input of each of the X splitters is configured to receive an Optical Time Domain Reflectometry, OTDR, signal and to split the received OTDR signal into Y OTDR sub-signals such that a total of N OTDR sub-signals are outputted from the X splitters. The arrangement further comprises an N*N Arrayed Waveguide Grating, AWG, and a first filter configured to mix a feeder signal comprising data communication from an Optical Line Termination, OLT, with one of the N OTDR sub-signals. One input of the AWG is configured to receive the mix of the feeder signal and the one OTDR sub-signal, and the remaining N-inputs of the AWG are each configured to receive a respective one of the N-remaining OTDR sub-signals.

Abstract: A Wavelength Adaptation Module and a method therein for adapting an Optical Time Domain Reflectometry, OTDR, signal for supervision of Optical Network Terminals, ONTs, in a Passive Optical Network, PON, are provided. The wavelength of the OTDR signal is adapted to have a selected wavelength to enable a splitter in a remote node to forward the OTDR signal to a dedicated group of ONTs in the PON, thereby supervising the fibre links between the remote node and the dedicated group of ONTs. Likewise, a remote node and a method therein for receiving an OTDR signal having a pre-selected wavelength from the Wavelength Adaptation Module and for outputting the OTDR signal to a dedicated group of ONTs with regards to the pre-selected wavelength of the received OTDR signal are provided.

Abstract: Methods and apparatuses for enabling supervision of fibres in an optical communication network, where a Central Office provides data signals to a Remote Node for distribution to Optical Network Terminals ONTs. The Central Office generates and sends test signals of different monitoring wavelengths associated to predefined groups of said ONTs, to the Remote Node. The Remote Node routes each test signal to a corresponding associated group of ONTs according to the wavelength of the test signal. When receiving a back-scattered and back-reflected test signal caused by a faulty optical fibre, the Central Office is able to identify the faulty optical fibre based on the wavelength of the back-scattered and back-reflected signal.

Abstract: A method and arrangement in an Optical Network Terminal, ONT for monitoring the state of an Optical Distribution Network, ODN, in a Passive Optical Network, PON, is provided. The ONT receives an optical signal, from an Optical Line Terminal, OLT, having optical power, Po,sat, causing a Semiconductor Optical Amplifier, SOA, comprised in the ONU, to reach a saturated state. One or more parameters are measured. The parameters relates to the power provided from a power source to the SOA during a predefined time period, where the SOA is in a saturated state during the predefined time period. Information relating to the measured parameters are provided to the OLT and thereby enabling the OLT to compare the current state of the ODN to a previously measured reference state of the ODN.

Abstract: A Wavelength Adaptation Module and a method therein for adapting an Optical Time Domain Reflectometry, OTDR, signal for supervision of Optical Network Terminals, ONTs, in a Passive Optical Network, PON, are provided. The wavelength of the OTDR signal is adapted to have a pre-selected wavelength to enable a splitter in a remote node to forward the OTDR signal to a dedicated group of ONTs in the PON, thereby supervising the fibre links between the remote node and the dedicated group of ONTs. Likewise, a remote node and a method therein for receiving an OTDR signal having a pre-selected wavelength from the Wavelength Adaptation Module and for outputting the OTDR signal to a dedicated group of ONTs with regards to the pre-selected wavelength of the received OTDR signal are provided.

Abstract: A wavelength shifter module and a method therein for tuning an OTDR signal to at least one pre-selected wavelength in a passive optical network (PON). The wavelength of the OTDR signal is shifted to a pre-selected wavelength to enable a remote node in the optical distribution network ODN of the PON to forward the OTDR signal to a specific drop section in the ODN. The invention also includes a remote node and a method in a remote node for receiving a wavelength shifted OTDR signal having a preselected wavelength and outputting the wavelength shifted OTDR signal to a specific drop section. Furthermore, the invention involves a method for determining the location of a fault section in a drop section.

Abstract: A client unit and a method are provided performing fault analysis in a Passive Optical Network, PON, by using Optical Time Domain Reflectometry, OTDR. The method comprises triggering a new OTDR measurement, wherein a previous reference measurement has been made indicating an original state of the PON. The method further comprises inserting an OTDR measurement signal into a multistage splitter before a last splitter stage of the multistage splitter, and wherein the last splitter stage is of ratio 2:N; and obtaining at least one new event location based on the OTDR measurement signal. Further, the method comprises calculating a fault magnitude at a given location by subtracting an event magnitude obtained from the new OTDR measurement from the reference OTDR measurement and taking into account the number of drop links connected to the last splitter stage in the reference measurement and the new measurement. Thereby, determination of position and severity of the fault locations is enabled.