Abstract: A photonic radio frequency, RF, signal generation apparatus has a source to output a coherent optical signal at a carrier frequency; an optical splitter to split the signal into a first and a second optical carrier signal; an RF signal generation apparatus generating an RF signal at an initial frequency; an optical modulation apparatus modulating the first and second signals at the initial frequency to generate optical harmonic signals around each signal; a first optical filter to select an nth order optical harmonic signal of a first sign, +n, of the optical harmonics around the first signal; a second optical filter to select the nth order optical harmonic signal of an opposite sign, ?n, of the optical harmonics around the second signal; and a combiner to combine the selected +n and ?n signals to generate an optical beat signal forming an output photonic RF signal.

Abstract: Embodiments described herein provide a waveguide for transmitting electromagnetic radiation. The waveguide comprising a core region, a cladding region extending around the core region; and a first layer of a material having a thickness of less than a skin depth of the material for electromagnetic radiation of a first wavelength; wherein the first layer is configured with a periodic refractive index and positioned within the waveguide such that a first surface polariton wave is excited at an interface between the core region and cladding region when electromagnetic radiation of the first wavelength is transmitted through the core region. There is also provided a method of manufacture of the waveguide.

Abstract: Embodiments described herein relate to methods and apparatus for generating electromagnetic radiation in an electro-optical apparatus.

Abstract: A method (100) for managing Optical Wireless Communication (OWC) in a User Equipment (UE) is disclosed, the UE being configured for Radio Frequency (RF) communication with a network and comprising at least two OWC receivers. The method comprises monitoring a captured luminous flux intensity at the OWC receivers (1 10) and, if a captured luminous flux intensity at at least one of the OWC receivers is above a viability threshold (120), selecting the OWC receiver having the highest captured luminous flux intensity (130) and extracting client data from an optical signal received on the selected OWC receiver (140). Also disclosed are a UE (300, 700) configured for RF communication with a network and for OWC, the UE comprising at least two OWC receivers, and a controller (500, 600) for managing OWC in a UE.

Abstract: Embodiments described herein relate to methods and apparatus for generating electromagnetic radiation in an electro-optical apparatus.

Abstract: A polarization controller is configured to control polarization of an optical signal. The polarization controller includes a first polarization rotator and a second polarization rotator controllable by control settings. The polarization controller includes a monitor unit configured to generate a monitoring value indicating a performance of the polarization controller. The polarization controller is configured to determine from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states. If operation is not in an optimal performance state, the polarization controller is further configured to select different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.

Abstract: A method for monitoring a passive optical network, the passive optical network comprising a plurality of network components, comprises receiving an alert message (200) from a fault detection system associated with the passive optical network, the alert message comprising an indication of one or more candidate locations for a detected fault in the passive optical network. The method further comprises accessing an inventory (202) of the plurality of network components, the inventory storing, for each of the plurality of network components, information comprising the network component location. The method further comprises identifying (204), based on the one or more candidate locations and the network component locations, one or more network components of the plurality of network components as candidates for the cause of the detected fault.

Abstract: Transmitting and receiving apparatuses, transmitting and receiving methods, and a transceiver for a phased array antenna are provided. The transmitting apparatus may comprise a laser light source configured to provide an optical beam comprising one or more spectral components. The transmitting apparatus may comprise a modulator configured to modulate the optical beam with a signal to be transmitted. The transmitting apparatus may comprise one or more group delay controlling units configured to add one or more controllable time delays to the one or more spectral components. Further, the transmitting apparatus may comprise a plurality of waveguides each having a chromatic dispersion configured to guide the optical beam, wherein the laser light source is tunable to control time delays added by the plurality of waveguides.

Abstract: Embodiments described herein provide a waveguide for transmitting electromagnetic radiation. The waveguide comprising a core region, a cladding region extending around the core region; and a first layer of a material having a thickness of less than a skin depth of the material for electromagnetic radiation of a first wavelength; wherein the first layer is configured with a periodic refractive index and positioned within the waveguide such that a first surface polariton wave is excited at an interface between the core region and cladding region when electromagnetic radiation of the first wavelength is transmitted through the core region. There is also provided a method of manufacture of the waveguide.

Abstract: A receiver (1) for a phased array antenna comprises a laser light source (2) arranged to provide an optical spectrum comprising a first spectral component having a first wavelength and a second spectral component having a second wavelength. The first wavelength is spaced from the second wavelength. A wavelength separator (4) is configured to separate the first spectral component from the second spectral component, such that the first spectral component is directed onto a first path (A) and the second spectral component is directed onto a second path (B). A first delay unit (16) is configured to add a controllable time delay to the first spectral component on the first path. A second delay unit (42) is configured to add the time delay to the second spectral component on the second path. A modulator (14) is configured to modulate the first spectral component on the first path with a received RF signal from the phased array antenna.

Abstract: A periodic phase modulation, having a period shorter than a symbol period, is applied as a source modulation, in addition to a symbol modulation, to signals transmitted between a transmitter and a receiver in a communication network. Symbol value elements can be sent from multiple transmitters (203, 303, 603, 703) to a receiver (607, 207) in the same symbol period can be processed on the basis of the source modulation without destructive interference. In some embodiments, the symbol value elements sent by different transmitters can be combined in the receiver. In some embodiments, symbol value elements sent by different transmitters can be distinguished in the receiver.

Abstract: A data center network node (28) comprises one or more switch (18,19,22,23) configured to link an optical transceiver (16,17) to an optical connection comprising a multi-core optical fiber (30) having a plurality of cores (31). For each core (31), the one or more switch (18,19,22,23) is configurable between a first configuration in which an optical signal on a said core (31) of the multi-core optical fiber bypasses the optical transceiver and a second configuration in which the optical transceiver is optically linked to the said core (31) of the multi-core optical fiber (30).

Abstract: A data center network node comprising at least one server connection for connecting to a server 6, a connection 7 for connecting the at least one server 6 to a first subnetwork. The first subnetwork is a conventional subnetwork which comprises at least one of a switch or a router. The node further comprises an optical receiver array 20 for connecting the node to an optical offload subnetwork, wherein the optical receiver array 20 comprises a plurality of optical receivers. The array is configured such that each receiver is connectable to an optical path within a multi-path optical connection. The node further comprises an optical transmitter array 23 for connecting the node to an optical offload subnetwork. The optical transmitter array comprises a plurality of optical transmitters. The array is configured such that each receiver is connectable to an optical path within a multi-path optical connection.

Abstract: A method for monitoring a passive optical network, the passive optical network comprising a plurality of network components, comprises receiving an alert message (200) from a fault detection system associated with the passive optical network, the alert message comprising an indication of one or more candidate locations for a detected fault in the passive optical network. The method further comprises accessing an inventory (202) of the plurality of network components, the inventory storing, for each of the plurality of network components, information comprising the network component location. The method further comprises identifying (204), based on the one or more candidate locations and the network component locations, one or more network components of the plurality of network components as candidates for the cause of the detected fault.

Abstract: A data center network node (28) comprises one or more switch (18,19,22,23) configured to link an optical transceiver (16,17) to an optical connection comprising a multi-core optical fiber (30) having a plurality of cores (31). For each core (31), the one or more switch (18,19,22,23) is configurable between a first configuration in which an optical signal on a said core (31) of the multi-core optical fiber bypasses the optical transceiver and a second configuration in which the optical transceiver is optically linked to the said core (31) of the multi-core optical fiber (30).

Abstract: A polarization controller (10;40) is configured to control polarization of an optical signal. The polarization controller comprises a first polarization rotator (18) and a second polarization rotator (28) controllable by control settings. The polarization controller comprises a monitor unit (34) configured to generate a monitoring value indicating a performance of the polarization controller. The polarization controller is configured to determine from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states (52). If operation is not in an optimal performance state, the polarization controller is further configured to select different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.

Abstract: An opto-electronic oscillator (10) comprising: an optical source (12) to generate an optical carrier signal having a carrier wavelength; an optical phase modulator (14) to apply a sinusoidal phase modulation to the optical carrier signal to generate two first order sidebands having a ? phase difference between them; an optical phase shifter (16) comprising an optical resonator configured to apply a substantially ? phase-shift to one of the first order sidebands at a preselected wavelength within an optical spectrum of said first order sideband; and a photodetector (18) configured to perform optical heterodyne detection of the optical carrier signal with both: said one of the first order sidebands substantially it phase shifted by the optical resonator; and the other of the first order sidebands, to generate an electrical carrier signal (20), and wherein a first part of the electrical carrier signal (20a) is delivered to an electrical output (22) and a second part of the electrical carrier signal (20b) is deli

Abstract: A data center network node (13) comprising a first data connection (22) for connecting at least one server to a conventional subnetwork comprising at least one of a switch or a router, an optical transceiver (14) comprising a transmitter (16) and a receiver (17), a second data connection (23) for connecting the at least one server to the optical transceiver, a switching arrangement (21) for linking the optical transceiver (14) to an offload subnetwork (10), the switching arrangement configurable between a first configuration (24) in which the offload subnetwork bypasses the optical transceiver and a second configuration (28) in which the optical transceiver is optically linked to the offload subnetwork.

Abstract: An optical source comprises a first laser arranged to generate a first optical signal having a first state of polarization (SOP) and a first optical frequency; a second laser arranged to generate a second optical signal having a second SOP, substantially orthogonal to the first SOP, and having a second optical frequency, different from the first optical frequency by a preselected frequency difference; a polarisation beam coupler arranged to combine the first optical signal and the second optical signal into a composite optical signal comprising both the first optical signal and the second optical signal having said substantially orthogonal SOPs; and an output arranged to output the composite optical signal.

Abstract: A method (100) for managing Optical Wireless Communication (OWC) in a User Equipment (UE) is disclosed, the UE being configured for Radio Frequency (RF) communication with a network and comprising at least two OWC receivers. The method comprises monitoring a captured luminous flux intensity at the OWC receivers (1 10) and, if a captured luminous flux intensity at at least one of the OWC receivers is above a viability threshold (120), selecting the OWC receiver having the highest captured luminous flux intensity (130) and extracting client data from an optical signal received on the selected OWC receiver (140). Also disclosed are a UE (300, 700) configured for RF communication with a network and for OWC, the UE comprising at least two OWC receivers, and a controller (500, 600) for managing OWC in a UE.