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3D images of moving objects can be achieved with a surveillance camera and four white light-emitting diodes. With these simple components, an imaging rate of 15 Hz is possible, limited by the camera framerate.
Integrated optical filters such as Bragg gratings are widely used in silicon-on-insulator technology for signal processing [1], telecommunications [2] and quantum processing [3]. Sidewall gratings offer a simple geometry that has been widely used for fabricating TE filters with high extinction ratios and accurate control over the grating stop-band and central wavelength [4]. However, a major drawback...
Autonomous mobile devices can self-locate, navigate and receive control signals using structured illumination from a light-emitting diode array. We present a prototype system and discuss the properties of the optical wireless control.
Arrays of GaN light-emitting diodes can be used for rapid display of pattern sequences or high speed parallel data transmission using different sites of the array. These operation modes can be combined with each other and are useful for light-fidelity networks with Gb/s capacity.
A silicon micro-ring device with tunable four-wave mixing efficiency is presented. The micro-ring is monolithically integrated with a dual polarisation filter based on a cascaded three ring resonator geometry. Four-wave mixing is demonstrated with signal and idler transmitted through the filter with only 1.8 dB of insertion loss. The pump light is rejected with over 62 dB extinction for both TE and...
An analysis of sidewall grating filters with sinusoidal perturbation is presented. Measurements indicate that the maximum extinction-ratio of the filters is limited by the polarisation scattering in the waveguide. We show that TM polarisation absorbers and filters offer a simple design solution that can provide extinction ratio values up to 60 dB.
Accurate self-orientation within a space can be achieved using only a simple photodetector and a remote Gallium Nitride micro-light-emitting diode array, emitting a time series of varying spatial illumination patterns onto the scene.
Integrated semiconductor laser devices are presented as extremely compact generators of ultra-short pulse trains. Control is demonstrated on a wide range of emission parameters including wavelength, pulse duration, repetition rate and emitted power. All device geometries require simple drive electronics, consisting of only constant current injection and reverse bias voltage control.
We discuss the development of silicon photonic microring resonators for the emission of optical vortex beams. These devices offer great potential for high capacity short-reach optical interconnects thanks to their compactness, low power consumption and fast reconfigurability.
We report on the design and characterisation of integrated silicon-on-insulator Bragg filters for polarisation selective operation. We show how the design of side and top waveguide gratings can be independently optimised for TE and TM polarisation. Device measurements show filter extinction ratios up to 40dB, strong polarisation selectivity and accurate control over the stop-band width.
Electrical switching of the orbital angular momentum (OAM) mode order emitted from an SOI microring resonator is reported. The integration of the microring with waveguide couplers is used to demonstrate modulation of the relative phase between pairs of OAM modes with opposite signs.
Orbital angular momentum (OAM) represents an additional degree of freedom of a light beam, to be added to the standard ones (e.g. polarization, wavelength) [1–2]. Previously, we have demonstrated an integrated device for OAM generation, in which the Whispering Gallery mode (WGM) of the micro-ring resonator to a propagating OAM mode by using an angular grating embedded within the resonator structure...
A compact silicon photonics multi-wavelength filter is demonstrated using superimposed sidewall Bragg gratings. We show arbitrary wavelength spacing with 8 superimposed gratings on a total footprint that is equivalent to a single Bragg grating device.
An integrated source of time-energy entangled photons is demonstrated through resonantly enhanced spontaneous four-wave mixing in a silicon micro-ring resonator. A Franson type set-up is employed to show the quantum interference between photon pairs with a visibility exceeding 90% and a violation of the Bell's inequality by more than 10 standard deviations. The high spectral brightness and the extremely...
Fast tuning of the Optical Angular Momentum (OAM) order of a vortex beam is demonstrated with 20µs switching times using a compact silicon photonic device.
On-chip electrical modulation of relative phase between pairs of optical vortices with opposite signs has been demonstrated, enabling useful functions in lab-on-chip, communications and sensing applications.
We present a silicon-on-insulator quantum photonic device able to generate and analyze two maximally entangled qubits. Quantum interference between resonant four-wave mixing sources, phase-stable frequency-selection, and quantum state tomography are shown.
We demonstrate an integrated silicon source of time-energy entangled photons. Entanglement is proved using a Franson type experiment, obtaining visibility exceeding 90% and a violation of the Bell's inequality by more than 10 standard deviations.
We present a microring-based integrated router in Silicon-on-Insulator technology suitable for optical networking at chip level. The switching functionalities in a 3-channels 10 Gbit/s WDM configuration are evaluated through the BER curves. Results show, for a BER of 10−9, a maximum power penalty of 7 dB on the less performing routing path.
We study, both theoretically and experimentally, emission of correlated photon-pairs by spontaneous four-wave-mixing in silicon integrated resonators. We show that the number of generated pairs in the quantum experiment is predicted by a classical experiment.
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