A device includes a dielectric layer, a plurality of grating structures, and a dielectric material between the plurality of grating structures and on top of the plurality of grating structures. The grating structures are arranged on the dielectric layer and separated from each other, the plurality of grating structures each having a bottom portion and top portion, the top portion having a first width and the bottom portion having a second width, the second width being larger than the first width.

A temperature compensation method for wavelength monitoring using spectrometers on photonic integrated chips and a related temperature-compensated wavelength monitoring device include an optical filter of the chip filters a source signal to provide at least one spectral reference line to a first spectrometer to detect thermal wavelength drifts thereof. At least one spectral line to be monitored is received by the same or another spectrometer of the chip to detect wavelength shifts thereof. The detected thermal drift of the reference line is compared to calibrated thermal drifts for the reference line which is associated with a calibrated thermal drift for the spectral response curve of the spectrometer receiving the spectral line to be monitored. A thermal drift rate for the response curve of the optical filter differs from a thermal drift rate for the response curve of the first spectrometer at least by an amount.

A fluid properties sensing system includes an optical sensor which generates a sensor signal based on received laser light, a light source which transmits laser light through a transmitting fiber to a sensor head, a receiver that detects a portion of the laser light from a receiving fiber through an evanescent field of the transmitting fiber when the laser light radiates through a transmitting fiber wall of the transmitting fiber and interacts with a fluid medium at an interface of the sensor and the fluid medium, and a processor. The fibers are coupled at one end through the evanescent field to form the sensor head disposed in a flow field and to interact with the fluid medium. The processor identifies a change in the sensor signal based on a detected portion of the laser light resulting from an interaction of the sensor head with the fluid medium.

A light conversion portion is constituted by a conversion material that converts infrared light to visible light. A reflection portion is fixed to a position on a main substrate at which the reflection portion faces an output end of an optical waveguide chip on the side from which light is output to an external space. The reflection portion includes a reflection surface that faces the output end and is inclined with respect to a plane of the main substrate such that a reflection direction is toward the upper side of the main substrate. The reflection surface reflects near infrared light.

A laser. In some embodiments, the laser includes an optical amplifier, and an output reflector. The output reflector may be configured to receive light from the optical amplifier and to reflect light at a first wavelength back toward the optical amplifier. The output reflector may include a wavelength-selective element, and a coupler configured to receive the light from the optical amplifier and to couple a portion of the light to the wavelength-selective element.

A demultiplexer for use in a wavelength division multiplexed system. The demultiplexer comprises: an input waveguide, configured to receive a wavelength division multiplexed signal; a demultiplexing element, configured to demultiplex the multiplexed signal received from the input waveguide into a plurality of multi-mode demultiplexed signal components; a multi-mode output waveguide, the multi-mode output waveguide being coupled to the demultiplexing element and configured to receive one of the multi-mode demultiplexed signal components; and a splitter, coupled to the multi-mode output waveguide, and configured to split the received multi-mode demultiplexed signal component into two single-mode outputs.

A connection structure of optical waveguide chips includes a base substrate (2003) in which grooves (2013) are formed, spacer optical fibers (2006) each disposed for a corresponding one of the grooves (2013) and fitted in the groove (2013) while partially projecting from the base substrate (2003), and silica-based PLCs (2001, 2002) that are a plurality of optical waveguide chips in each of which grooves (2007) fitted on the projecting portions of the spacer optical fibers (2006) are formed at positions of an optical waveguide layer (2008) facing the grooves (2013), and each of which is mounted on the base substrate (2003) while being supported by the spacer optical fibers (2006). The silica-based PLCs (2001, 2002) are mounted on the base substrate (2003) such that incident/exit end faces of the optical waveguide layers (2008) face each other.

An optical module includes an interface electrically connected to an external device to receive a data signal to be transmitted, a signal processor configured to perform serialization and signal modulation on the received data signal, an optical transceiver configured to generate an optical transmission signal by receiving a direct current (DC) light source, in which a plurality of light sources having different wavelengths are multiplexed, from an optical power supply and performing optical modulation thereon through the serialized and modulated data signal, and an optical fiber connector configured to output the generated optical transmission signal to the external device and receive an optical reception signal from the external device.

A device includes a first package connected to an interconnect substrate, wherein the interconnect substrate includes conductive routing; and a second package connected to the interconnect substrate, wherein the second package includes a photonic layer on a substrate, the photonic layer including a silicon waveguide coupled to a grating coupler and to a photodetector; a via extending through the substrate; an interconnect structure over the photonic layer, wherein the interconnect structure is connected to the photodetector and to the via; and an electronic die bonded to the interconnect structure, wherein the electronic die is connected to the interconnect structure.

An optical subassembly includes a planar dielectric waveguide structure that is deposited at temperatures below 400 C. The waveguide provides low film stress and low optical signal loss. Optical and electrical devices mounted onto the subassembly are aligned to planar optical waveguides using alignment marks and stops. Optical signals are delivered to the submount assembly via optical fibers. The dielectric stack structure used to fabricate the waveguide provides cavity walls that produce a cavity, within which optical, optoelectronic, and electronic devices can be mounted. The dielectric stack is deposited on an interconnect layer on a substrate, and the intermetal dielectric can contain thermally conductive dielectric layers to provide pathways for heat dissipation from heat generating optoelectronic devices such as lasers.