Refractory anchoring devices include a main body and a mounting feature for mounting to a thermal vessel. The main body has the shape of two end-to-end Y's forming a central segment, branch segments extending from ends of the central segment, and extension segments extending from the branch segments, to collectively form four unenclosed cell openings that are semi-hexagonally shaped. Some embodiments include reinforcement segments extending into respective cell openings, voids extending through respective adjacent branch and extension segments, an underbody gap under the central segment, a single stud-welding stud for the mounting feature, and/or a collar-and-stud connection between the anchor main body and a stud-welding stud of the mounting feature. Refractory anchoring systems and methods include an array of the refractory anchoring devices arranged and mounted so that the unenclosed semi-hexagonal cell openings of adjacent anchoring devices cooperatively form substantially hexagonal cells.

An optical filter comprising a first lens, and first and second optical elements. The first lens has an optical axis, configured to focus beams propagating parallel to the optical axis at a focal point. The first optical element has a first semi-reflective surface, the first semi-reflective surface being curved and having a first radius of curvature around a first centre of curvature on the optical axis. The second optical element has a second semi-reflective surface. The first radius of curvature is between 1 and 10,000 times the distance between the first semi reflective surface and the focal point along the optical axis. The first and second semi-reflective surfaces are arranged to form a resonator. The first lens and the first and second semi-reflective surfaces are arranged along the optical axis such that light is transmittable along an optical path through the lens and the resonator. The optical filter further comprises one or more expansion elements located outside of the optical path, and arranged such that expansion of the expansion elements causes relative movement of the first and second semi-reflective surfaces.

The invention relates to an electrically controlled interference colour filter comprising at least two transparent electrodes, at least one nematic liquid crystal layer and alignment layers for alignment of the liquid crystals. When an electrical field is applied the liquid crystals can be realigned and thus the transmission wavelength range of the interference colour filter can be shifted.

Provided is an optical wavelength multi/demultiplexing circuit with a high rectangular transmission loss spectrum that is able to secure loss flatness of a transmission band, maintain/reduce a guard bandwidth of wavelength channel spacing, and broaden a transmission bandwidth. The circuit uses a multimode waveguide for a connecting part between a field modulation device and an AWG. The field modulation device is constituted by a common input waveguide, an optical branching unit, optical delay lines, a multiplex interference unit, and a mode converter/multiplexer.

A phase retarder and an optical comb filter are disclosed. The phase retarder includes a polarization beam splitter, a first air arm, and a second air arm, where the polarization beam splitter is configured to decompose a beam into a first light component propagated in a first direction and a second light component propagated in a second direction, the first direction is perpendicular to the second direction; the first air arm is disposed on a second side wall of the polarization beam splitter, and is configured to receive the first light component and reflect it back; and the second air arm is disposed on a third side wall of the polarization beam splitter, and is configured to receive the second light component and reflect it back. Two light components interfere, and the interference light is emitted from a fourth side wall of the polarization beam splitter.

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of the optical fighter using a two-photon polymerization process on a photosensitive polymer by a three-dimensional micromachining device. The three-dimensional microscopic optical structure having a hinged optical layer pivotally connected to a distal portion of a suspended structure. A reflective layer is deposited on a mirror surface of the hinged optical layer while in an open position. The hinged optical layer is subsequently positioned in the closed position to align the mirror surface to at least partially reflect a light signal back through the optical fiber.

An optical apparatus, comprising a semiconductor substrate, a dielectric layer located on the semiconductor substrate, wherein a membrane portion of the dielectric layer is located over a cavity in a surface of the semiconductor substrate, a resistive heater located on the membrane portion, the resistive heater being controllable by a current applied to the resistive heater and an etalon optical filter located on the resistive heater and over the cavity, an optical passband of the etalon optical filter being wavelength tunable by the resistive heater. A method of manufacturing the optical apparatus is also disclosed.

Disclosed herein is an integrated photonics device including a frequency stabilization subsystem for monitoring and/or adjusting the wavelength of light emitted by one or more light sources. The device can include one or more selectors that can combine, select, and/or filter light along one or more light paths, which can include light emitted by a plurality of light sources. Example selectors may include, but are not limited to, an arrayed waveguide grating (AWG), a ring resonator, a plurality of distributed Bragg reflectors (DBRs), a plurality of filters, and the like. Output light paths from the selector(s) can be input into one or more detector(s). The detector(s) can receive the light along the light paths and can generate one or more signals as output signal(s) from the frequency stabilization subsystem. A controller can monitor the wavelength and can adjust or generate control signal(s) for the one or more light sources to lock the monitored wavelength to a target wavelength (or within a targeted range of wavelengths).

Provided is an optical wavelength multi/demultiplexing circuit with a high rectangular transmission loss spectrum that is able to secure loss flatness of a transmission band, maintain/reduce a guard bandwidth of wavelength channel spacing, and broaden a transmission bandwidth. The circuit uses a multimode waveguide for a connecting part between a field modulation device and an AWG. The field modulation device is constituted by a common input waveguide, an optical branching unit, optical delay lines, a multiplex interference unit, and a mode converter/multiplexer.