Abstract: An optoelectronic device. The optoelectronic device comprising: a rib waveguide provided on a substrate of the device, the rib waveguide comprising a ridge portion and a slab portion; a heater, disposed within the slab portion; a thermally isolating trench, adjacent to the rib waveguide, and extending into the substrate of the device; and a thermally isolating cavity within the substrate, which is directly connected to the thermally isolating trench, and which extends across at least a part of a width of the rib waveguide between the rib waveguide and the substrate.

Abstract: A photonic integrated circuit, an optoelectronic modulator, and a method of modulating light in a photonic integrated circuit are provided. The photonic integrated circuit comprises: an input waveguide which, in use, receives light in a superposition of two polarisation modes of the waveguide; a polarisation splitter, connected to the input waveguide, and configured to provide, at a first output, light in a first polarisation mode of the two polarisation modes of the waveguide and, at a second output, light in a second polarisation mode of the two polarisation modes of the waveguide; a first polarisation rotator, connected to the first output of the polarisation splitter, and configured to rotate light received therefrom from the first polarisation mode to the second polarisation mode; an optoelectronic modulator, having a first modulation waveguide connected to the first polarisation rotator and a second modulation waveguide connected to the second output of the polarisation splitter.

Abstract: An optoelectronic device, including: a rib waveguide, the rib waveguide including: a ridge portion, which includes a temperature-sensitive optically active region, and a slab portion, positioned adjacent to the ridge portion; the device further comprising a heater, disposed on top of the slab portion wherein a part of the heater closest to ridge portion is at least 2 ?m away from the ridge portion. The device may also have a heater provided with a bottom cladding layer, and may also include various thermal insulation enhancing cavities.

Abstract: A Mach-Zehnder waveguide modulator. In some embodiments, the Mach-Zehnder waveguide modulator includes a first arm including a first optical waveguide, and a second arm including a second optical waveguide. The first optical waveguide includes a junction, and the Mach-Zehnder waveguide modulator further includes a plurality of electrodes for providing a bias across the junction to enable control of the phase of light travelling through the junction.

Abstract: A modulator. In some embodiments, the modulator includes a portion of an optical waveguide, the waveguide including a rib extending upwards from a surrounding slab. The rib may have a first sidewall, and a second sidewall parallel to the first sidewall. The rib may include a first region of a first conductivity type, and a second region of a second conductivity type different from the first conductivity type. The second region may have a first portion parallel to and extending to the first sidewall, and a second portion parallel to the second sidewall. The first region may extend between the first portion of the second region and the second portion of the second region.

Abstract: An optoelectronic device. The optoelectronic device comprising: a rib waveguide provided on a substrate of the device, the rib waveguide comprising a ridge portion and a slab portion; a heater, disposed within the slab portion; a thermally isolating trench, adjacent to the rib waveguide, and extending into the substrate of the device; and a thermally isolating cavity within the substrate, which is directly connected to the thermally isolating trench, and which extends across at least a part of a width of the rib waveguide between the rib waveguide and the substrate.

Abstract: A polarization rotator and a polarization stabilizer. The polarization rotator includes a rib waveguide. The rib waveguide including: a slab portion; and a ridge portion, which is disposed along a surface of the slab portion. The slab portion has a first slab region whose width, as measured in a direction perpendicular to a guiding direction of the waveguide, increases from a first slab width to a second slab width along a first length, and the ridge portion has a first ridge region whose width, as measured in the same direction as the slab widths, decreases from a first ridge width to a second ridge width along the same first length; such that the rotator is configured to rotate the polarization of light during its transmission through the rib waveguide.

Abstract: A ring optical resonator is formed on a substrate. An outer circumferential surface of the resonator substantially confines one or more circumferential resonant optical modes. The resonator is positioned above a void formed in the substrate and is supported above the void by a portion of a material layer on the substrate that extends radially inward above the void from an outer circumferential edge of the void to the outer circumferential surface of the resonator. An optical waveguide can be integrally formed on the substrate and traverses a portion of the material layer above the void. The optical waveguide and the ring optical resonator are arranged and positioned so as to establish evanescent optical coupling between them. Q-factors of 108 or more have been achieved with a silica resonator and silicon nitride waveguide integrally formed on a silicon substrate.

Abstract: A polarization rotator and a polarization stabilizer. The polarization rotator includes a rib waveguide. The rib waveguide including: a slab portion; and a ridge portion, which is disposed along a surface of the slab portion. The slab portion has a first slab region whose width, as measured in a direction perpendicular to a guiding direction of the waveguide, increases from a first slab width to a second slab width along a first length, and the ridge portion has a first ridge region whose width, as measured in the same direction as the slab widths, decreases from a first ridge width to a second ridge width along the same first length; such that the rotator is configured to rotate the polarization of light during its transmission through the rib waveguide.

Abstract: A photonic integrated circuit, an optoelectronic modulator, and a method of modulating light in a photonic integrated circuit are provided. The photonic integrated circuit comprises: an input waveguide which, in use, receives light in a superposition of two polarisation modes of the waveguide; a polarisation splitter, connected to the input waveguide, and configured to provide, at a first output, light in a first polarisation mode of the two polarisation modes of the waveguide and, at a second output, light in a second polarisation mode of the two polarisation modes of the waveguide; a first polarisation rotator, connected to the first output of the polarisation splitter, and configured to rotate light received therefrom from the first polarisation mode to the second polarisation mode; an optoelectronic modulator, having a first modulation waveguide connected to the first polarisation rotator and a second modulation waveguide connected to the second output of the polarisation splitter.

Abstract: A polarization rotator and a polarization stabilizer. The polarization rotator includes a rib waveguide. The rib waveguide including: a slab portion; and a ridge portion, which is disposed along a surface of the slab portion. The slab portion has a first slab region whose width, as measured in a direction perpendicular to a guiding direction of the waveguide, increases from a first slab width to a second slab width along a first length, and the ridge portion has a first ridge region whose width, as measured in the same direction as the slab widths, decreases from a first ridge width to a second ridge width along the same first length; such that the rotator is configured to rotate the polarization of light during its transmission through the rib waveguide.

Abstract: An optoelectronic device, including: a rib waveguide, the rib waveguide including: a ridge portion, which includes a temperature-sensitive optically active region, and a slab portion, positioned adjacent to the ridge portion; the device further comprising a heater, disposed on top of the slab portion wherein a part of the heater closest to ridge portion is at least 2 ?m away from the ridge portion. The device may also have a heater provided with a bottom cladding layer, and may also include various thermal insulation enhancing cavities.

Abstract: A ring optical resonator is formed on a substrate. An outer circumferential surface of the resonator substantially confines one or more circumferential resonant optical modes. The resonator is positioned above a void formed in the substrate and is supported above the void by a portion of a material layer on the substrate that extends radially inward above the void from an outer circumferential edge of the void to the outer circumferential surface of the resonator. An optical waveguide can be integrally formed on the substrate and traverses a portion of the material layer above the void. The optical waveguide and the ring optical resonator are arranged and positioned so as to establish evanescent optical coupling between them. Q-factors of 108 or more have been achieved with a silica resonator and silicon nitride waveguide integrally formed on a silicon substrate.

Abstract: A method of etching active quantum nanostructures provides the step of laterally etching of an intermediate active quantum nanostructure layer interposed between cladding layers. The lateral etching can be carried out on at least one side of the intermediate active quantum nanostructure layer selectively, with respect to the cladding layers to define at least one lateral recess or spacing in the intermediate active quantum nanostructure layer and respective lateral protrusions of cladding layers protruding with respect to the intermediate active quantum nanostructure layer. This method can be applied to create devices including active quantum nanostructures such as, for example, three-dimensional photonic crystals, a photonic crystal double-slab and a photonic crystal laser.

Abstract: A method and apparatus for battery gauging in a portable terminal are provided. In the battery gauging method, it is determined in a low-power mode whether a listening interval occurs for detecting the presence of a received signal. The remaining battery capacity is detected if the listening interval occurs. An interrupt signal is transmitted to the second processor, operating in a low-power mode, if the remaining battery capacity is less than or equal to a threshold. Upon receipt of the interrupt signal, the second processor wakes up to interrupt the power of the portable terminal.

Abstract: A method of etching active quantum nanostructures provides the step of laterally etching of an intermediate active quantum nanostructure layer interposed between cladding layers. The lateral etching can be carried out on at least one side of the intermediate active quantum nanostructure layer selectively, with respect to the cladding layers to define at least one lateral recess or spacing in the intermediate active quantum nanostructure layer and respective lateral protrusions of cladding layers protruding with respect to the intermediate active quantum nanostructure layer. This method can be applied to create devices including active quantum nanostructures such as, for example, three-dimensional photonic crystals, a photonic crystal double-slab and a photonic crystal laser.

Abstract: A method and apparatus for battery gauging in a portable terminal are provided. In the battery gauging method, it is determined in a low-power mode whether a listening interval occurs for detecting the presence of a received signal. The remaining battery capacity is detected if the listening interval occurs. An interrupt signal is transmitted to the second processor, operating in a low-power mode, if the remaining battery capacity is less than or equal to a threshold. Upon receipt of the interrupt signal, the second processor wakes up to interrupt the power of the portable terminal.