Abstract: A Mach-Zehnder Interferometer (MZI) includes a first arm having one or more first delay sections and respective first undercuts beneath the first delay sections, the first delay section(s) having a total first length and a first width. A second arm includes one or more second delay section(s) and respective second undercuts beneath the second delay section(s), the second delay section(s) having a total second length and a second width. The total first length is longer than the total second length, and the first width is less than the second width. The first width and the second width are selected to be less than a threshold width. For widths above the threshold width, variations in index-to-width tolerance are anticorrelated with respective variations in index-to-thickness tolerance and index-to-temperature tolerance. For widths below the threshold width, variations in index-to-width tolerance are correlated with respective variations in index-to-thickness tolerance and index-to-temperature tolerance.

Abstract: A Mach-Zehnder Interferometer (MZI) includes a pair of waveguides, an optical input configured to split light received at the optical input between the pair of waveguides, and respective ring resonator modulators located on the pair of waveguides, the respective ring resonator modulators comprising respective pn-junctions having respective capacitances connected in series. The MZI further includes a common driver configured to receive a differential electrical signal with data encoded therein and to control, using the differential electrical signal, respective n-sides of the respective pn-junctions to control the respective ring resonator modulators to respectively modulate the light into respective optical signals. The MZI further includes a common voltage bias configured to provide a common voltage to respective p-sides of the respective pn-junctions.

Abstract: Devices to mitigate polarization mode dispersion are provided. An example device comprises: an input coupler configured to receive an optical signal comprising a first portion in a first polarization mode and a second portion in a second polarization mode, the second polarization mode about perpendicular to the first polarization mode; an output and/or an optical detector; and one or more optical components configured to convey the optical signal from the input coupler to the output and/or optical detector, one or more of the input coupler and the optical component(s) introducing a total differential group delay between the first and second portions. The optical component(s) comprising: a rotating component configured to rotate the first polarization mode of the first portion to the second polarization mode and rotate the second polarization mode of the second portion to the first polarization mode, to adjust the total differential group delay.

Abstract: A line-shaped heater and an optical resonator with portions on opposite sides of the line-shaped heater are provided. In particular a device provided herein includes: one or more inputs; one or more outputs; one or more optical waveguides configured to: receive an optical signal from at least one of the one or more inputs; and convey the optical signal to at least one of the one or more outputs; an optical resonator configured to modulate or filter the optical signal; and a heater configured to heat the optical resonator, the heater being line-shaped and having a first side and a second side opposite the first side, and the optical resonator comprising a first portion at the first side of the heater and a second portion at the second side of the heater.

Abstract: An apparatus for controlling a level of gas in a closed environment from a gas supply having a gas sensor for detecting the level of gas in the closed environment. The apparatus has a valve in communication with the gas supply which is automatically opened without human interaction, monitoring and adjustment to release gas from the gas supply into the environment when the level of gas in the environment goes below a first predetermined level and which is automatically closed without human interaction, monitoring and adjustment to stop gas from being released from the gas supply into the environment when the level of gas in the environment goes above a second predetermined level. A method for controlling a level of gas in a closed environment from a gas supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: A line-shaped heater and an optical resonator with portions on opposite sides of the line-shaped heater are provided. In particular a device provided herein includes: one or more inputs; one or more outputs; one or more optical waveguides configured to: receive an optical signal from at least one of the one or more inputs; and convey the optical signal to at least one of the one or more outputs; an optical resonator configured to modulate or filter the optical signal; and a heater configured to heat the optical resonator, the heater being line-shaped and having a first side and a second side opposite the first side, and the optical resonator comprising a first portion at the first side of the heater and a second portion at the second side of the heater.

Abstract: Devices to mitigate polarization mode dispersion are provided. An example device comprises: an input coupler configured to receive an optical signal comprising a first portion in a first polarization mode and a second portion in a second polarization mode, the second polarization mode about perpendicular to the first polarization mode; an output and/or an optical detector; and one or more optical components configured to convey the optical signal from the input coupler to the output and/or optical detector, one or more of the input coupler and the optical component(s) introducing a total differential group delay between the first and second portions. The optical component(s) comprising: a rotating component configured to rotate the first polarization mode of the first portion to the second polarization mode and rotate the second polarization mode of the second portion to the first polarization mode, to adjust the total differential group delay.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: Fluid treatment and recycling systems are provided. In various embodiments, systems are provided that are portable or semi-portable such that the systems can be conveyed to various locations or work sites. Systems are provided with a plurality of filtration elements or stages. Systems of the present disclosure are operable to remove coarse and fine particulates from a quantity of fluid such that the fluid is rendered suitable for further use.

Abstract: A trailer device is provided with pressure washing features and devices. The trailer device is convertible between at least a first and mode of transport, wherein a first mode comprises a towing mode, and a second mode comprises a push or manual operation mode. The device also comprises various on-board features and control systems such that a fully-functional pressure washing unit is provided that is easily transporting between locations.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: An adiabatic elliptical optical coupler device is provided comprising: a substrate having an edge; a first waveguide on the substrate, the first waveguide comprising a constant-width region and a tapered region terminating at the edge of the substrate, the tapered region having a smaller width at the edge than at the constant-width region; and, a pair of second waveguides on the substrate, and located on either side of the tapered region, each of the pair of the second waveguides terminating at the edge at a first end and extending to a second end adjacent the constant-width region, and distal the first end; at least a portion of each of the pair of second waveguides being tapered, and optically coupled to the first waveguide to transition a mode of an optical signal in the first waveguide from an elliptical mode at the edge towards a confined mode.

Abstract: A trailer device is provided with pressure washing features and devices. The trailer device is convertible between at least a first and mode of transport, wherein a first mode comprises a towing mode, and a second mode comprises a push or manual operation mode. The device also comprises various on-board features and control systems such that a fully-functional pressure washing unit is provided that is easily transporting between locations.

Abstract: An adiabatic elliptical optical coupler device is provided comprising: a substrate having an edge; a first waveguide on the substrate, the first waveguide comprising a constant-width region and a tapered region terminating at the edge of the substrate, the tapered region having a smaller width at the edge than at the constant-width region; and, a pair of second waveguides on the substrate, and located on either side of the tapered region, each of the pair of the second waveguides terminating at the edge at a first end and extending to a second end adjacent the constant-width region, and distal the first end; at least a portion of each of the pair of second waveguides being tapered, and optically coupled to the first waveguide to transition a mode of an optical signal in the first waveguide from an elliptical mode at the edge towards a confined mode.