Telefonaktiebolaget Lm Ericsson (publ)

Gemma Vall-Llosera

Francesco Testa

Kim Laraqui

Patryk Urban

Boris Dortschy

Wei-Ping Huang

Neiva Lindqvist

Ahsan Javed Awan

Stefan Höst

Fabio Bottoni

Sumsam Ullah Khan

Stefan Dahlfort

Methods and apparatus are disclosed, including an example of a method of determining a distance between a first point and a second point. The method includes manipulating quantum states of at least first and second qubits of a quantum computing device based on a test vector representing the first point and a training vector representing the second point, performing quantum interference between the test vector and the training vector, performing a measurement on one or more of the qubits to determine the distance, and determining the distance from the measurement.

Determining a distance

Systems and methods for controlling optical powers of optical channels in an optical communications network comprising a plurality of nodes is described herein. The method comprises obtaining a reference optical power. The method also includes determining an optical power of an optical channel generated by an optical transmitter of a node. The method further includes applying an attenuation to the optical channel to reduce the optical power of the optical channel to the reference optical power. In some implementations, the method is performed by a network controller operating in the optical communications network.

Optical transceiver and method of controlling optical powers of optical channels

In an optical transceiver, an optical transmitter coupled to a reconfigurable optical channel-add apparatus has first and second add paths, an add micro-ring resonator, and first and second optical attenuators, reconfigurable to selectively block an optical channel from an optical transmitter in one of the first and second add paths. The add micro-ring resonator is reconfigurable selectively to add an optical channel from the first add path to an optical waveguide to travel towards the first add-drop port or to add an optical channel from the second add path to the optical waveguide to travel towards the second add-drop port. An optical receiver is coupled to a reconfigurable optical channel-drop apparatus having a drop micro-ring resonator, and first and second drop paths. The drop micro-ring resonator is reconfigurable selectively to drop an optical channel travelling from the first add-drop port from the optical waveguide to the first drop path or to drop an optical channel travelling from the second add-drop port from the optical waveguide to the second drop path.

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&#xd7;Domain Reflectometry, O&#xd7;DR, measurement over the fiber line. Additionally, the network unit analyses a trace from the O&#xd7;DR measurement for localizing the fault or for deciding that the indicated fault is not a fault along the fiber line.

Network unit and method for monitoring a fiber line

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.

Monitoring of a passive optical network (PON)

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.

Device, remote node and methods for PON supervision

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.

PON supervision using OTDR measurements

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.

Methods and apparatuses for supervision of optical networks

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. SCDM device demultiplexes electromagnetic signal into at least two electromagnetic signals and outputs.

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Järfälla, Sweden

Gemma Vall-Llosera