Abstract: An optical circuit includes a frequency comb laser outputting N channels of light on a single path, an optical splitter splitting the output from laser into three light paths, a first light path as a laser output, a second light path as a reference laser, and a third light path. A high quality factor cavity filter is coupled with the third path. A first wavelength demultiplexer (WDM) is coupled with the second light path configured to demultiplex the light in the second light path into N outputs. A second WDM is coupled with the third light path configured to demultiplex the light in the third light path into N outputs. A mixing circuit is coupled with the N outputs from the first WDM and the N outputs from the second WDM, and has 2N outputs. The mixing circuit is configure to directionally couple the 2 signals for each wavelength (?N) and to output into 2N waveguides the directionally coupled light paths.

Abstract: Examples of the disclosure relate to an apparatus. The apparatus includes a housing portion and a flexible portion. The housing portion includes one or more heat sources. The flexible portion is configured to be moved between a closed configuration and an open configuration wherein in the closed configuration the flexible portion is housed in the housing portion and in the open configuration the flexible portion is positioned outside of the housing. The flexible portion includes a flexible display and an oscillating heat pipe. The oscillating heat pipe is coupled to the one or more heat sources in the housing portion. The oscillating heat pipe is flexible and configured to move with the flexible portion between the closed configuration and the open configuration. One or more condenser regions of the oscillating heat pipe are positioned in the flexible portion.

Abstract: An apparatus for cooling electronic circuitry components and photonic components. In examples of the disclosure at least one photonic component is positioned overlaying at least one electronic circuitry component. In examples of the disclosure there is also provided a spacer for spacing the at least one electronic circuitry component and the at least one photonic component, wherein the spacer for spacing are thermally insulating. In examples of the disclosure there is also provided a first heat transfer configured to remove heat from the at least one electronic circuitry component, and a second heat transfer configured to remove heat from the at least one photonic component.

Abstract: Examples of the disclosure relate to apparatus for cooling components such as electronic circuitry components and photonic components. A first component and a second component are provided on the same surface of a substrate. At least one temperature control means, such as a thermoelectric cooler. is configured to control the temperature of at least one of the components. The apparatus also comprises a plurality of heat transfer means that extend through the substrate from the first surface to the second surface. The plurality of heat transfer means enable heat to be transferred from the components to a heat pipe provided on the second surface of the substrate. This enables heat to be transferred through the substrate and away from the components and so can reduce the amount of heat that spreads laterally across the substrate. This allows for efficient removal of heat from the components and reduces heat transfer between the components.

Abstract: Examples of the disclosure relate to an apparatus. The apparatus comprises a housing portion and a flexible portion. The housing portion comprises one or more heat sources. The flexible portion is configured to be moved between a closed configuration and an open configuration wherein in the closed configuration the flexible portion is housed in the housing portion and in the open configuration the flexible portion is positioned outside of the housing. The flexible portion comprises a flexible display and an oscillating heat pipe. The oscillating heat pipe is coupled to the one or more heat sources in the housing portion. The oscillating heat pipe is flexible and configured to move with the flexible portion between the closed configuration and the open configuration. One or more condenser regions of the oscillating heat pipe are positioned in the flexible portion.

Abstract: An optical data transmitter having M serially optically connected electro-absorption modulators (EAMs) individually driven using ON-OFF-keying (OOK) electronics, where M is an integer greater than one. In an example embodiment, the optical data transmitter can be used to generate an intensity-modulated optical signal carrying symbols of a 2M-level unipolar pulse-amplitude-modulation constellation. The OOK electronics enables the DC bias voltages and/or AC amplitudes of the two-level drive signals applied to different EAMs to be individually controllable to achieve desired uniform or non-uniform separation between the constellation levels. In at least some embodiments, temperatures of different EAMs may also be individually controllable. In various embodiments, the EAMs may operate in reflection or in transmission.

Abstract: Examples of the disclosure relate to an oscillating heat pipe. The oscillating heat pipe includes a channel, a wick structure and a vent. The channel is configured to enable flow of working fluid between at least one condenser region and at least one evaporator region. The wick structure is in fluidic connection with the channel so as to enable working fluid to flow from the channel into the wick structure. The vent is configured to enable working fluid in an, at least partial, vapour phase to be returned from the wick structure to the channel.

Abstract: A device and method are provided for more efficient thermal management of optoelectronic devices. A microfluidic distribution apparatus embedded with the optoelectronic device uses a working fluid in phase change to passively remove heat from an optoelectronic device. The working fluid undergoes phase change through various conversions between a liquid state and a two-phase liquid-vapor state to facilitate evaporation and condensation processes as the working fluid is distributed through micro-structures in the embedded microfluidic distribution apparatus. Passive two-phase cooling provides high thermal performance due to the use of the latent heat of a fluid in phase change, as well as the presence of favorable two-phase flow regimes at micro-scale dimensions.

Abstract: An apparatus for cooling electronic circuitry components and photonic components. In examples of the disclosure at least one photonic component is positioned overlaying at least one electronic circuitry component. In examples of the disclosure there is also provided a spacer for spacing the at least one electronic circuitry component and the at least one photonic component, wherein the spacer for spacing are thermally insulating. In examples of the disclosure there is also provided a first heat transfer configured to remove heat from the at least one electronic circuitry component, and a second heat transfer configured to remove heat from the at least one photonic component.

Abstract: A photonic integrated circuit includes a slot optical waveguide having an optical core with sub-wavelength slot therein that is partially filled with a first lower-index material having a negative thermo-optic coefficient. The slot may also include a second lower-index material having a positive thermo-optic coefficient. The relative volume of the first lower-index material within the slot may be configured to provide athermal or nearly-athermal operation. Example applications include integrated AWG MUX/DEMUX devices, Mach-Zehnder modulators, and micro-ring resonators or modulators implemented with silicon-based or silicon-nitride based slot waveguides with reduced sensitivity to temperature changes.

Abstract: An optical data transmitter having M serially optically connected electro-absorption modulators (EAMs) individually driven using ON-OFF-keying (OOK) electronics, where M is an integer greater than one. In an example embodiment, the optical data transmitter can be used to generate an intensity-modulated optical signal carrying symbols of a 2M-level unipolar pulse-amplitude-modulation constellation. The OOK electronics enables the DC bias voltages and/or AC amplitudes of the two-level drive signals applied to different EAMs to be individually controllable to achieve desired uniform or non-uniform separation between the constellation levels. In at least some embodiments, temperatures of different EAMs may also be individually controllable. In various embodiments, the EAMs may operate in reflection or in transmission.

Abstract: Photonic integrated circuits utilizing interferometric effects, such as wavelength multiplexers/demultiplexers, include a free-space coupling region having two core layers that have thermo-optic coefficients of opposite sign. The two core layers are configured to provide athermal or nearly-athermal operation. Described examples include integrated array waveguide grating devices and integrated echelle grating devices. Example material systems include LNOI and SOI.

Abstract: A photonic integrated circuit includes a slot optical waveguide having an optical core with sub-wavelength slot therein that is partially filled with a first lower-index material having a negative thermo-optic coefficient. The slot may also include a second lower-index material having a positive thermo-optic coefficient. The relative volume of the first lower-index material within the slot may be configured to provide athermal or nearly-athermal operation. Example applications include integrated AWG MUX/DEMUX devices, Mach-Zehnder modulators, and micro-ring resonators or modulators implemented with silicon-based or silicon-nitride based slot waveguides with reduced sensitivity to temperature changes.

Abstract: Photonic integrated circuits utilizing interferometric effects, such as wavelength multiplexers/demultiplexers, include a free-space coupling region having two core layers that have thermo-optic coefficients of opposite sign. The two core layers are configured to provide athermal or nearly-athermal operation. Described examples include integrated array waveguide grating devices and integrated echelle grating devices. Example material systems include LNOI and SOI.

Abstract: The temperature sensitivity of a reflective electro-absorption modulator can be reduced through the use, e.g., in the optical cavity thereof, of optical materials having positive and negative thermo-optic coefficients (TOCs). In some embodiments, a multiple-quantum-well structure of the modulator comprises positive-TOC materials, and a Bragg reflector bounding the optical cavity comprises one or more negative-TOC materials. In some embodiments, the thicknesses of the layers of positive- and negative-TOC materials are selected such that the average refractive index along the optical path through the modulator is approximately temperature independent. In some embodiments, the optical length of the optical cavity is an integer multiple of a nominal operating wavelength.

Abstract: A device and method are provided for more efficient thermal management of optoelectronic devices. A microfluidic distribution apparatus embedded with the optoelectronic device uses a working fluid in phase change to passively remove heat from an optoelectronic device. The working fluid undergoes phase change through various conversions between a liquid state and a two-phase liquid-vapor state to facilitate evaporation and condensation processes as the working fluid is distributed through micro-structures in the embedded microfluidic distribution apparatus. Passive two-phase cooling provides high thermal performance due to the use of the latent heat of a fluid in phase change, as well as the presence of favorable two-phase flow regimes at micro-scale dimensions.

Abstract: Optical transmitters, receivers, and transceivers implemented using a plurality of surface-coupled optical devices that can be manufactured on the same planar substrate and then post-processed to provide some of the devices with different respective partially transparent front mirrors compatible with and/or customized for different respective optical functions. When appropriately electrically biased and driven, different subsets of such devices can operate as lasers, optical modulators, optical amplifiers, and photodetectors, respectively. In this manner, an integrated array of such devices can be customized to provide the optical functions needed for the intended product. For example, an optical transmitter can be constructed using an integrated array that comprises three surface-coupled optical devices configured to operate as a laser, an optical modulator, and an optical amplifier, respectively.

Abstract: Optical transmitters, receivers, and transceivers implemented using a plurality of surface-coupled optical devices that can be manufactured on the same planar substrate and then post-processed to provide some of the devices with different respective partially transparent front mirrors compatible with and/or customized for different respective optical functions. When appropriately electrically biased and driven, different subsets of such devices can operate as lasers, optical modulators, optical amplifiers, and photodetectors, respectively. In this manner, an integrated array of such devices can be customized to provide the optical functions needed for the intended product. For example, an optical transmitter can be constructed using an integrated array that comprises three surface-coupled optical devices configured to operate as a laser, an optical modulator, and an optical amplifier, respectively.

Abstract: An optical data transmitter in which surface-coupled reflective electro-absorption modulators are placed into different interferometer arms and operated in a manner that enables the optical data transmitter to transmit an optical output signal modulated using PAM, QPSK, or QAM modulation. In some embodiments, the optical data transmitter is configured to generate a PDM optical output signal by using two such interferometers and a quarter-wavelength plate configured to cause the output polarizations of the two interferometers to be mutually orthogonal. The electro-absorption modulators are surface-coupled in the sense that, in operation, each of these devices receives input light and outputs modulated light along a direction that is substantially orthogonal to the main plane of the device.

Abstract: An optical radiation detection system (100) comprising: an optical medium (1) structured to define a region (5) suitable for transmitting an optical radiation and being associated to at least one electric parameter varying as a function of the optical radiation concerning said region; at least one electrode (2, 3) electrically coupled to the optical medium (1), and spaced from said region (5), an electric power generator (4) connected to said at least one electrode (2) and structured to provide an electric signal (Se) to be applied to the optical medium. Further, the system comprises an electric measuring circuit (50) connected to said at least one electrode (2) and structured to provide a measuring electric signal (SM) representing a variation of said at least one electric parameter.