An optical device for a quantum random number generator comprising: a source of phase randomised pulses of light, the source of phase randomised pulses of light further comprising a plurality of gain-switched lasers, each gain-switched laser having an output, and each gain-switched laser being configured to emit a stream of pulses such that the phase of each pulse in the stream of pulses is randomised, and an optical pulse combiner, the optical pulse combiner being configured to receive streams of pulses from the output of each gain-switched laser, combine the streams of pulses with one another into a combined stream of pulses and direct the combined stream of pulses into at least one output of the optical pulse combiner, the at least one output of the optical pulse combiner being the output of the source of phase randomised pulses of light; wherein the source of phase randomised pulses of light is configured such that the streams of pulses of light emitted by the plurality of gain-switched lasers are temporally offset relative to one another, a phase measurement element, the phase measurement element being configured to receive the combined stream of pulses from the output of the source of phase randomised pulses of light; and an optical detector, the optical detector being optically coupled to the phase measurement element.

An example device in accordance with an aspect of the present disclosure includes a first layer and a second layer to be bonded to the first layer. The first and second layers are materials that generate gas byproducts when bonded, and the first and/or second layers is/are compatible with photonic device operation based on a separation distance. At least one bonding interface layer is to establish the separation distance for photonic device operation, and is to prevent gas trapping and to facilitate bonding between the first layer and the second layer.

An example device in accordance with an aspect of the present disclosure includes a first layer and a second layer to be bonded to the first layer. The first and second layers are materials that generate gas byproducts when bonded, and the first and/or second layers is/are compatible with photonic device operation based on a separation distance. At least one bonding interface layer is to establish the separation distance for photonic device operation, and is to prevent gas trapping and to facilitate bonding between the first layer and the second layer.

A laser light source may include an arrangement of surface-emitting semiconductor lasers to which a voltage is applied such that an operating current is below the threshold current and an intrinsic emission of the surface-emitting semiconductor laser is prevented. The laser light source also comprises a first semiconductor laser which emits radiation that enters the surface-emitting semiconductor laser such that induced emission takes place via the injection locking mechanism and the individual surface-emitting semiconductor lasers emit laser light having the same wavelength and polarisation direction as the irradiated radiation. The emission frequency of the first semiconductor laser can be changed by changing the operating current.

A laser light source may include an arrangement of surface-emitting semiconductor lasers to which a voltage is applied such that an operating current is below the threshold current and an intrinsic emission of the surface-emitting semiconductor laser is prevented. The laser light source also comprises a first semiconductor laser which emits radiation that enters the surface-emitting semiconductor laser such that induced emission takes place via the injection locking mechanism and the individual surface-emitting semiconductor lasers emit laser light having the same wavelength and polarisation direction as the irradiated radiation. The emission frequency of the first semiconductor laser can be changed by changing the operating current.

A solid-state device, and use and formation thereof. The device includes a light emitter (102) that emits light with abeam propagation direction and includes an emitter epitaxial layer stack (940); a light routing medium (103) in optical communication with the light emitter; and a light detector (104) in optical communication with the light routing medium, which detects light emitted by the light emitter and includes a detector epitaxial stack (945). The light emitter and detector are monolithically formed on a semiconductor substrate. The emitter and detector epitaxial layer stacks include different pluralities of layers of a single epitaxial layer stack. The beam propagation direction is either in-plane with the single epitaxial layer stack and the light detector detects light out of plane with the single epitaxial layer stack, or out of plane with the single epitaxial layer stack and the light detector detects light in plane with the single epitaxial layer stack.

A wafer includes a buried substrate; a layer of silicon (100) disposed on the buried substrate and forming multiple U-shaped grooves, wherein each U-shaped groove comprises a bottom portion and silicon sidewalls (111) at an angle to the buried substrate; a buffer layer disposed within the multiple U-shaped grooves; and multiple gallium nitride (GaN)-based structures having vertical sidewalls disposed within and protruding above the multiple U-shaped grooves, the multiple GaN-based structures each including cubic gallium nitride (c-GaN) formed at merged growth fronts of hexagonal gallium nitride (h-GaN) that extend from the silicon sidewalls (111).

A light emitting device includes: a base having a first stepped portion and a second stepped portion; a light emitting element; an electronic member configured to be irradiated by light emitted from the light emitting element; a first wiring region located on the first stepped portion; a second wiring region located on the second stepped portion; wires connected to the light emitting element and the electronic member. The wires includes a first and second wires. The first wire has a first end that is connected to the first wiring region, and a second end. The second wire has a first end that is connected to the second wiring region, and a second end. A position of the second end of the first wire relative to the bottom face is lower than a position of the second end of the second wire relative to the bottom face.

A wavelength tunable laser device includes: a first mirror; a second mirror; an optical amplifier provided between the first mirror and the second mirror; a wavelength tunable filter provided between the first mirror and the second mirror; and an optical waveguide coupling the optical amplifier and the wavelength tunable filter. The optical waveguide includes a first waveguide formed with a first width and a second waveguide formed with a second width wider than the first width.

A wavelength tunable laser device includes: a first mirror; a second mirror; an optical amplifier provided between the first mirror and the second mirror; a wavelength tunable filter provided between the first mirror and the second mirror; and an optical waveguide coupling the optical amplifier and the wavelength tunable filter. The optical waveguide includes a first waveguide formed with a first width and a second waveguide formed with a second width wider than the first width.