Abstract: An RF transition assembly (300) for enabling a radiofrequency transition between an RF transmission layer (301) of an electronic device and a conductor (309) which is electrically connected (317) to the RF transmission layer (301). The conductor (309) extends generally orthogonal to the RF transmission layer (301). The assembly comprises an open coaxial structure (313) located adjacent to an edge of the RF transmission layer (301). The open coaxial structure (313) comprises a cavity (315) extending therethrough for receiving the conductor (309). The cavity (315) comprises an opening facing the edge of the RF transmission layer (301) so as to direct electromagnetic radiation towards the RF transmission layer (301).

Abstract: A Mach-Zehnder modulator for modulating optical signals, and comprising: a plurality of modulating waveguide sections; at least one bias electrode in electrical communication with at least one modulating waveguide section and configured to apply at least one electrical bias signal to one or more of the modulating waveguide sections; and an output optical combiner comprising a plurality of inputs and a plurality of outputs, wherein the plurality of inputs of the combiner are in optical communication with output sides of the plurality of modulating waveguide sections, and wherein a plurality of the outputs of the combiner are monitor outputs.

Abstract: An optical communications apparatus comprising a host (100) and an optical module (200) comprising a Mach-Zehnder modulator (202), MZM, wherein the optical module is removably connected to the host via a connection path, the optical communications apparatus comprising: a signal generator (101) at the host, configured to generate a plurality of calibration signals at a plurality of frequencies; a host interface (102) configured to transmit the calibration signals to the optical module via the connection path; a module interface (201) configured to receive the transmitted calibration signals; wherein the MZM is configured to use the calibration signals to modulate a laser light source (206) and biased to a point at which average output power is proportional to the output modulated signal; an optical detector configured to measure an average magnitude of an output of the MZM when each of the calibration signals is used to modulate the laser light source; one of a host calibration unit (103) and a module calibrat

Abstract: There is described a transmitter device for transmitting an optical signal in the form of a plurality of subcarrier channels having different wavelengths. The device comprises first and second optical carrier emitters for emitting light in first and second subcarriers at first and second frequencies or polarizations respectively. First and second modulators are provided for modulating the first and second subcarriers with first and second modulation signals. An interleaver is provided for interleaving the first and second modulated subcarriers into the optical signal. First and second digital signal processing units are configured to pre-emphasize the first and second modulation signals to compensate for a wavelength-dependent power transfer function of the interleaver.

Abstract: A Mach-Zehnder modulator for modulating optical signals, and comprising: a plurality of modulating waveguide sections; at least one bias electrode in electrical communication with at least one modulating waveguide section and configured to apply at least one electrical bias signal to one or more of the modulating waveguide sections; and an output optical combiner comprising a plurality of inputs and a plurality of outputs, wherein the plurality of inputs of the combiner are in optical communication with output sides of the plurality of modulating waveguide sections, and wherein a plurality of the outputs of the combiner are monitor outputs.

Abstract: Methods and apparatus for use in coherent transmission and reception of optical data signals. An integrated optics block (100) for use in a coherent optical transmitter comprising: a beam splitter (102) configured to split an input light signal into first and second input light signals, to output the first input light signal for use in an optical transmitter chip and to output the second input light signal for use as a local oscillator signal; a polarization combiner (104) configured to combine first and second received modulated light signals to form an output; and a polarization rotator (106) configured to rotate the polarization of the second modulated light signal such that it is substantially orthogonal to the polarization of the first modulated light signal prior to combining.

Abstract: The invention relates to an optoelectronic assembly. The optoelectronic assembly comprises one or more optoelectronic components and a housing. The housing comprises an outer wall electrically connected to the one or more optoelectronic elements. The housing is configured to provide an electrical interface between the one or more optoelectronic components and an external electronic device. The electrical connection between the outer wall and the one or more optoelectronic components comprises an electrically conductive element. The electrically conductive element is supported on a dielectric material, such that the dielectric material provides structural support to the electrically conductive element between the one or more optoelectronic components and the outer wall.

Abstract: There is described an optoelectronic device having a housing and a chip housed by the housing. At least a portion of the chip protrudes through an aperture in a wall of the housing. There is further provided an optoelectronic module comprising such an optoelectronic device and electronic control circuitry adapted to control the operation of the optoelectronic device.

Abstract: Sacrificial optical test structures are constructed upon a wafer of pre-cleaved optical chips for testing the optical functions of the pre-cleaved optical chips. The sacrificial optical structures are disabled upon the cleaving the optical chips from the wafer and the cleaved optical chips can be used for their desired end functions. The test structures may remain on the cleaved optical chips or they may be discarded.

Abstract: An optical waveguide arrangement is provided which comprises an active ridge waveguide structure 12 formed by etching of a semiconductor substrate 1, 2, 3. There is also provided an auxiliary waveguide-like structure 8 formed on the substrate adjacent the active ridge waveguide structure 12 to control the etched profile of the active waveguide structure. The arrangement of the auxiliary structure 8 on the substrate controls the etched profile over the cross-section of the active waveguide structure 12 and along the length of the active waveguide structure 12. Advantageously, this arrangement reduces or eliminates the disadvantages associated with etch-process induced asymmetries in the shape of closely spaced waveguides.

Abstract: A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a non-driven region, wherein at least one of the reflectors is a distributed Bragg reflector section configured to have a tunable reflection spectrum, wherein control electrodes are provided to at least the optical gain section, and the distributed Bragg reflector section, and wherein the non-driven region has a length of at least 100 ?m, is without an electrical contact directly contacting onto the epitaxially grown side of the non-driven region, and the non-driven region is without a reflective Bragg grating within the epitaxial layers of the non-driven region.

Abstract: The invention relates to a folded Mach-Zehnder modulator. The modulator may comprise a beam splitter configured to split an input light beam into a plurality of light beams. The modulator may comprise a plurality of Mach-Zehnder devices configured to receive one or more of the plurality of light beams. The modulator may comprise a U-turn section configured to receive light beams from the Mach-Zehnder devices and to change the direction of the light beams by substantially 180 degrees. The modulator may comprise a polarisation management section configured to combine light beams received from the U-turn section and to output a polarisation multiplexed phase modulated light beam.

Abstract: There is described an optical modulation system for transmitting modulated optical light. The system comprises an electro-optic modulator having at least two arms through which light is transmitted and an imbalance electrode located on at least one arm. A current source is configured to inject current into the imbalance electrode for modifying the phase of light passing through the arm. A dither generator is configured to modulate the injected current, or bias voltage applied to at least one of the arms, with a dither signal. A phase sensitive detector is configured to detect an error in the phase of light emitted by the modulator. An operating point controller is configured to monitor the detected phase error and adjust the current injected into the imbalance arm so as to compensate for the detected error and thereby control an operating point of the modulator.

Abstract: Optical devices are disclosed consisting of optical chips (planar lightwave circuits) which have optically symmetric or matching designs and properties and optical components which create asymmetry in the optical devices. The devices find application in detection in coherent and non-coherent optical communications systems.

Abstract: A widely tunable multi-mode semiconductor laser containing only two electrically active sections, being an optical gain section and a tunable distributed Bragg reflector section adapted to reflect at a plurality of wavelengths, wherein the gain section is bounded by the tunable distributed Bragg reflector section and a broadband facet reflector, and wherein the tunable distributed Bragg reflector section comprises a plurality of discrete segments capable of being selectively tuned, wherein the reflection spectra of one or more segments of the tunable distributed Bragg reflector section can be tuned lower in wavelength to reflect with the reflection spectrum of a further segment of the tunable distributed Bragg reflector section to provide a wavelength range of enhanced reflectivity. An optical transmitter comprising a light source that is such a widely tunable multi-mode semiconductor laser.

Abstract: According to a first aspect of the present invention there is provided an apparatus for performing power equalization and phase correction of two signals (400). The apparatus comprises a first hybrid coupler (401) configured to operate as a power combiner, and a second hybrid coupler (402) configured to operate as a power divider, wherein the apparatus is configured to provide an output (406) of the first hybrid coupler as an input (407) to the second hybrid coupler.

Abstract: Sacrificial optical test structures are constructed upon a wafer of pre-cleaved optical chips for testing the optical functions of the pre-cleaved optical chips. The sacrificial optical structures are disabled upon the cleaving the optical chips from the wafer and the cleaved optical chips can be used for their desired end functions. The test structures may remain on the cleaved optical chips or they may be discarded.

Abstract: An enclosure for a laser package the enclosure being configured to receive a laser component within the enclosure, and further configured to receive for a driver integrated circuit (IC) (34) on the exterior of the enclosure, wherein the enclosure comprises first external electrical contacts (52) electrically connected to respective first IC electrical contacts (60), and second IC electrical contacts (62) electrically connected to respective first internal electrical contacts (64), wherein the first and second IC electrical contacts (60, 62) are configured for electrical connection to the driver IC (34). Heat dissipation of the driver IC is improved for the IC being mounted outside of the enclosure.

Abstract: A photonic assembly is described. The assembly comprises a substrate. An optical modulator (100) in or on the substrate has an output port coupled to an output waveguide (106) mounted in or on the substrate. A spiller waveguide (107, 108) is mounted in or on the substrate. The spiller waveguide (107, 108) has an input end (109, 110) physically separated from but proximate to the output waveguide (106) so as to collect light spilt from the output port or output waveguide (106). The modulator (106) may be a MZI modulator.

Abstract: The present invention discloses an optical fibre (20) for coupling to an optical source (18) which includes a core (22) and a tip portion (36). The core (22) is for receiving light directed from the optical source along an optical axis; wherein the core is expanded near one end of the optical fibre, and the expanded core (24) having a diameter larger than other portions of the core that are not expanded. The tip portion (36) is on the end of the optical fibre, wherein the tip portion further includes an endmost face (26), the endmost face being non-perpendicular to the optical axis. A coupling system including such an optical fibre and a method of fabricating a coupling device for the optical fibre are also disclosed. The optical fibre as provided by the present invention not only enables high coupling efficiency with different laser mode sizes, but also reduces the back reflected laser from the optical fibre which may otherwise damage the laser semiconductor chip.