Abstract: An optical node (100) is disclosed. The optical node (100) comprises first and second line ports (104, 106) for Wavelength Division Multiplexing (WDM) signals and first and second pluralities of local add/drop ports (108, 110) for optical signals. The optical node further comprises a wavelength selective switch (112), coupled between the first and second line ports (104, 106) and configured to drop optical signals from a WDM signal traversing the optical node between the first and second line ports (104, 106), and a node optical combiner (114) coupled between the first and second line ports (104, 106) and configured to add optical signals to a WDM signal traversing the optical node between the first and second line ports (104, 106).

Abstract: An integrated circuit optical interconnect for connecting a first circuit part arranged to output an optical signal and a second circuit part arranged to receive an optical signal. The integrated circuit optical interconnect comprises a body comprising a glass material. The glass material has embedded therein an optical waveguide arrangement having an input, located at a surface of the body, for coupling to the first circuit part, and an output, located at a surface of the body, for coupling to the second circuit part. The optical waveguide arrangement comprises at least two optical waveguide segments extending in different directions through the glass material and at least one reflecting part arranged between the two optical waveguide segments, for directing an optical signal from one of the optical waveguide segments to the other of the optical waveguide segments.

Abstract: An optical beam spot size convertor is provided having a body. The body comprises a first optical waveguide having a first refractive index and a plurality of second optical waveguides each having a second refractive index higher than the first refractive index. The first optical waveguide is arranged to receive an input optical beam. The first optical waveguide is further arranged such that light from the input optical beam is coupled from the first optical waveguide into the plurality of second optical waveguides. The body further comprises an output optical waveguide and a reflective part coupled to the plurality of second optical waveguides and to the output optical waveguide. The reflective part is arranged to focus optical beams received from the plurality of second optical waveguides into a single optical beam which is directed to the output optical waveguide.

Abstract: There is provided an optical switch. The optical switch comprises a first optical waveguide, a second optical waveguide, a first optical ring resonator and a second optical ring resonator. The first optical ring resonator is arranged between the first optical waveguide and the second optical waveguide, wherein the first optical ring resonator is capable of coupling an optical signal travelling along the first optical waveguide in a first direction to the second optical waveguide such that the optical signal travels in a second direction along the second optical waveguide. The second optical ring resonator is arranged between the first optical waveguide and the second optical waveguide; wherein the second optical ring resonator is capable of coupling an optical signal travelling along the first optical waveguide in the first direction to the second optical waveguide such that the optical signal travels in a third direction along the second optical waveguide opposite to the second direction.

Abstract: A device (100) for processing a signal, the device comprising a polarization module (102) configured to receive a multi-wavelength optical input signal (Si) comprising a plurality of wavelengths, and for each wavelength. The polarization module is configured to convert a component of each wavelength having a first polarization mode into a converted component having a second, different, polarization mode. The device further comprises a processing module (104,106,114,128) configured to combine the converted component of each wavelength with a direct component of each wavelength received with said second polarization mode. The processing module is configured to generate a multi-wavelength optical output signal (So) solely having said second polarization mode.

Abstract: 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.

Abstract: A wavelength selective optical switching arrangement (23) comprises a set of input ports (61), a set of output ports (65); a switching matrix; and a plurality of de-multiplexers each comprising an aggregate port (62) and a plurality of tributary ports (64), each aggregate port being connected to an input port and each tributary port being connected to the switching matrix (57), the switching matrix being coupled between the tributary ports and the output ports. The wavelength selective optical switching arrangement is configured to receive at an input port a group of optical signals, each optical signal being transmitted on a different wavelength and being assigned to one of a plurality of destination nodes.

Abstract: An optical switch (10) comprising: input ports (12, 14) arranged to receive optical signals from directions D1 to Dn; output ports (16, 18) arranged to output optical signals to the said directions; drop ports (20); add ports (22); a first switch array (24) arranged to receive from a first said input port (12) optical signals at a plurality of wavelengths, and comprising switch elements (26) each arranged to selectively direct optical signals to a respective drop port.

Abstract: A method of manufacturing a coupling element configured to couple light between an optical device and one or more optical fiber comprises forming one or more waveguide in the silica. The one or more waveguide having a refractive index configured to guide the light between the optical device and the optical fiber. The forming of the one or more waveguide comprises photo-inducing a refractive index variation of the silica material.

Abstract: A device (100) for processing a signal, the device comprising a polarization module (102) configured to receive a multi-wavelength optical input signal (Si) comprising a plurality of wavelengths, and for each wavelength. The polarization module is configured to convert a component of each wavelength having a first polarization mode into a converted component having a second, different, polarization mode. The device further comprises a processing module (104,106,114,128) configured to combine the converted component of each wavelength with a direct component of each wavelength received with said second polarization mode. The processing module is configured to generate a multi-wavelength optical output signal (So) solely having said second polarization mode.

Abstract: An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.

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: An optical node (100) is disclosed. The optical node (100) comprises first and second line ports (104, 106) for Wavelength Division Multiplexing (WDM) signals and first and second pluralities of local add/drop ports (108, 110) for optical signals. The optical node further comprises a wavelength selective switch (112), coupled between the first and second line ports (104, 106) and configured to drop optical signals from a WDM signal traversing the optical node between the first and second line ports (104, 106), and a node optical combiner (114) coupled between the first and second line ports (104, 106) and configured to add optical signals to a WDM signal traversing the optical node between the first and second line ports (104, 106).

Abstract: A transport network (10) is configured to connect a plurality of remote radio units (3) with a plurality of digital units (5) in a radio access network. The transport network comprises an electronic cross-connect (31) common to the plurality of remote radio units and digital units, and a control unit (32) configured to control the electronic cross-connect. The transport network further comprises an optical link (40) between the electronic cross-connect and remote radio units. The electronic cross-connect is a multi-layer switch. The electronic cross-connect is configured to switch data flows between one or more of said plurality of digital units (5) and one or more of said plurality of remote radio units (3).

Abstract: A transport network is configured to connect one or more optical rings of optical add and drop devices with one or more digital units in a radio access network. The transport network comprises a first electronic cross-connect and a second electronic cross-connect. A switch is provided for connecting the first electronic cross-connect and/or the second electronic cross-connect to the one or more digital units. The first and second electronic cross-connects are each coupled to at least one of the one or more optical rings of optical add and drop devices.

Abstract: An optical source (10) comprising: a first laser (12) arranged to generate a first optical signal (14) having a first state of polarization and a first optical frequency; a second laser (16) arranged to generate a second optical signal (18, 48, 78) having a second state of polarization, substantially orthogonal to the first state of polarization, and having a second optical frequency, different to the first optical frequency by a preselected frequency difference, ??; a polarization beam coupler (20) 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 states of polarization; and an output (22) arranged to output the composite optical signal (24).

Abstract: An optical source (10) comprising: a first laser (12) arranged to generate a first optical signal (14) having a first state of polarization and a first optical frequency; a second laser (16) arranged to generate a second optical signal (18, 48, 78) having a second state of polarization, substantially orthogonal to the first state of polarization, and having a second optical frequency, different to the first optical frequency by a preselected frequency difference, ??; a polarization beam coupler (20) 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 states of polarization; and an output (22) arranged to output the composite optical signal (24).

Abstract: A silicon photonic device comprises a silicon core having a core refractive index and a structure formed in the silicon core. The structure comprises a first refractive index variation pattern across the core in a first direction (x) and having a first modulation depth (H1), and a second refractive index variation pattern across the core in a second, orthogonal, direction (y) and having a second modulation depth (H2), less than the first modulation depth. The first refractive index variation pattern overlays the second refractive index variation pattern, forming a three-dimensional structure. The first refractive index variation pattern only supports propagation of light having a TM mode between the first direction and a third direction (z) and the second refractive index variation pattern only supports propagation of light having a TE mode between the second direction and the third direction.

Abstract: An integrated circuit optical interconnect for connecting a first circuit part arranged to output an optical signal and a second circuit part arranged to receive an optical signal. The integrated circuit optical interconnect comprises a body comprising a glass material. The glass material has embedded therein an optical waveguide arrangement having an input, located at a surface of the body, for coupling to the first circuit part, and an output, located at a surface of the body, for coupling to the second circuit part. The optical waveguide arrangement comprises at least two optical waveguide segments extending in different directions through the glass material and at least one reflecting part arranged between the two optical waveguide segments, for directing an optical signal from one of the optical waveguide segments to the other of the optical waveguide segments.

Abstract: An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.