A sensing device is for sensing an outer surface of a roll of material. An infrared (IR) laser source is configured to direct IR laser radiation to the outer surface of the roll of material. A single photon avalanche diode (SPAD) detector is configured to receive reflected IR laser radiation from the outer surface of the roll of material. A controller is coupled to the IR laser source and the SPAD detector to determine a distance to the outer surface of the roll of material based upon a time-of-flight of the IR laser radiation.

A method for forming optical devices. The method includes providing a gallium nitride substrate member having a crystalline surface region and a backside region. The method also includes subjecting the backside region to a laser scribing process to form a plurality of scribe regions on the backside region and forming a metallization material overlying the backside region including the plurality of scribe regions. The method removes at least one optical device using at least one of the scribe regions.

A technique related to a semiconductor chip is provided. An optical gain chip is attached to a semiconductor substrate. An integrated photonic circuit is on the semiconductor substrate, and the optical gain chip is optically coupled to the integrated photonic circuit thereby forming a laser cavity. The integrated photonic circuit includes an active intra-cavity thermo-optic optical phase tuner element, an intra-cavity optical band-pass filter, and an output coupler band-reflect optical grating filter with passive phase compensation. The active intra-cavity thermo-optic optical phase tuner element, the intra-cavity optical band-pass filter, and the output coupler band-reflect optical grating filter with passive phase compensation are optically coupled together.

A tunable laser includes a reflective silicon optical amplifier (RSOA) with a reflective end and an interface end and an array of narrow-band reflectors, which each have a different center wavelength. It also includes a silicon-photonic optical switch, having an input port and N output ports that are coupled to a different narrow-band reflector in the array of narrow-band reflectors. The tunable laser also includes an optical waveguide coupled between the interface end of the RSOA and the input of the silicon-photonic optical switch. The frequency of this tunable laser can be tuned in discrete increments by selectively coupling the input port of the silicon-photonic optical switch to one of the N output ports, thereby causing the RSOA to form a lasing cavity with a selected narrow-band reflector coupled to the selected output port. The tunable laser also includes a laser output optically coupled to the lasing cavity.

A solid-state light source with built-in access resistance modulation is described. The light source can include an active region configured to emit electromagnetic radiation during operation of the light source. The active region can be formed at a p-n junction of a p-type side with a p-type contact and a n-type side with a n-type contact. The light source includes a control electrode configured to modulate an access resistance of an access region located on the p-type side and/or an access resistance of an access region located on the n-type side of the active region. The solid-state light source can be implemented in a circuit, which includes a voltage source that supplies a modulation voltage to the control electrode to modulate the access resistance(s).

After forming a first trench extending through a top semiconductor layer and a buried insulator layer and into a handle substrate of a semiconductor-on-insulator (SOI) substrate, a dielectric waveguide material stack including a lower dielectric cladding layer, a core layer and an upper dielectric cladding layer is formed within the first trench. Next, at least one lateral bipolar junction transistor (BJT), which can be a PNP BJT, an NPN BJT or a pair of complementary PNP BJT and NPN BJT, is formed in a remaining portion of the top semiconductor layer. After forming a second trench extending through the dielectric waveguide material stack to re-expose a portion of a bottom surface of the first trench, a laser diode is formed in the second trench.

An optical amplifier device includes: an optical waveguide core; an active gain material layer stack; and a dielectric material between the active gain material layer stack and the optical waveguide core. The optical waveguide core includes an input portion, a middle portion, an output portion and tapers. The middle portion is connected to the input and output portions via the tapers. The tapers widen outwardly, whereby the middle portion has an effective refractive index that is smaller than an effective refractive index of any of the input and output portions. The active gain material layer stack includes III-V semiconductor material layers having different refractive indices so as to possess an effective refractive index that is larger than the effective refractive index of the middle portion. The active gain material layer stack extends relative to a subsection of the optical waveguide core that includes the middle portion and tapers.

A group III-nitride semiconductor device comprises a light emitting semiconductor structure comprising a p-type layer and an n-type layer operable as a light emitting diode or laser. On top of the p-type layer there is arranged an n+ or n++-type layer of a group III-nitride, which is transparent to the light emitted from the underlying semiconductor structure and of sufficiently high electrical conductivity to provide lateral spreading of injection current for the light-emitting semiconductor structure.

This photonic transmitter includes a layer made of dielectric material, a sublayer made of doped III-V crystalline material extending directly over the layer made of dielectric material, a laser source including the sublayer made of doped III-V crystalline material, a modulator including a waveguide formed by proximal ends facing first and second electrodes and that segment of the layer made of dielectric material which is interposed between these proximal ends, and a zone composed only of one or more solid dielectric materials, which extends from a distal end of the second electrode to a substrate, and under the entirety of the distal end of the second electrode.

A light source device includes at least one first wiring, a plurality of second wirings, a plurality of light emitting elements each having a lower-surface-side electrode connected to a respective one of the at least one first wiring, a plurality of protective elements each having a lower-surface-side electrode connected to a respective one of the plurality of second wirings each corresponding to a respective one of the plurality of light emitting elements, each of the plurality of protective elements connected to a respective one of the plurality of light emitting elements, a plurality of first wirings each connecting an upper-surface-side electrode of each of the plurality of light emitting elements and a respective one of the plurality of second wirings, a plurality of second wires each connecting the upper-surface-side electrodes of two adjacent ones of the protective elements; and a plurality of third wires each connecting an upper-surface-side electrode of a respective one of the plurality of protective elements and a corresponding one of the at least one first wiring. The upper-surface-side electrodes of the plurality of light emitting elements and the upper-surface-side electrodes of the plurality of protective elements are of a same polarity, and the plurality of first wires are disposed below the plurality of second wires.