Abstract: Systems and methods for environmentally insensitive high-performance fiber-optic gyroscopes are provided. In one embodiment, a loop closure electronics apparatus for a fiber optic gyroscope having an optical phase modulator characterized by a transfer function that includes an error component of at least second order is provided. The apparatus comprises: a first digital circuit that generates a digital bias modulation signal; a second digital circuit that generates a digital feedback signal; at least one digital-to-analog converter that produces an electrical signal that drives the phase modulator from the digital bias modulation signal and the digital feedback signal; and a compensator that includes an analog filter of at least second order and a digital filter of at least second order, wherein the analog filter and the digital filter pre-filter the electrical signal to compensate for the error component.

Abstract: Systems and methods for environmentally insensitive high-performance fiber-optic gyroscopes are provided. In one embodiment, a loop closure electronics apparatus for a fiber optic gyroscope having an optical phase modulator characterized by a transfer function that includes an error component of at least second order is provided. The apparatus comprises: a first digital circuit that generates a digital bias modulation signal; a second digital circuit that generates a digital feedback signal; at least one digital-to-analog converter that produces an electrical signal that drives the phase modulator from the digital bias modulation signal and the digital feedback signal; and a compensator that includes an analog filter of at least second order and a digital filter of at least second order, wherein the analog filter and the digital filter pre-filter the electrical signal to compensate for the error component.

Abstract: An apparatus and method for detecting an agent utilizes a substrate, a waveguide on the substrate, a light source, a photo-detector, an optical coupler on the substrate, and a processor. The light source is configured to emit light into the waveguide. The photo-detector is configured to detect light. The optical coupler is configured to direct a first portion of light propagating from the waveguide towards the photo-detector and to direct a second portion of the light propagating from the waveguide back into the waveguide. The waveguide and the optical coupler at least partially form a resonator. A substance is at least one of embedded within the waveguide and adjacent to the waveguide. The substance is reactive to the agent. The processor detects a change in a resonance lineshape of the resonator caused by the reaction of the substance to the agent.

Abstract: Methods and devices for polarizing light in a proton exchange polarizer where cross-coupling of unwanted modes of light is reduced with an integrated spatial filter. An optically transmissive substrate such as a substrate created from LiNbO3 or LiTaO3 has side surfaces, which reflect unguided TM mode light. The light originates from an input fiber. The input fiber is connected to the substrate at one end and an output fiber is connected to receive guided TE mode light at the opposite end. The spatial filter is positioned at the primary reflection position of the light with respect to the sides of the polarizer. To improve extinction further, the spatial filter can also be located at secondary reflection points in another alternate embodiment.

Abstract: Methods and devices for polarizing light in a proton exchange polarizer where cross-coupling of unwanted modes of light is reduced with an integrated spatial filter. An optically transmissive substrate such as a substrate created from LiNbO3 or LiTaO3 has side surfaces, which reflect unguided TM mode light. The light originates from an input fiber. The input fiber is connected to the substrate at one end and an output fiber is connected to receive guided TE mode light at the opposite end. The spatial filter is positioned at the primary reflection position of the light with respect to the sides of the polarizer. To improve extinction further, the spatial filter can also be located at secondary reflection points in another alternate embodiment.

Abstract: A method is provided for stabilizing an electro-optic substrate employed in a waveguide device. The method comprises cleaning a surface of the substrate, and exposing the device to a reactive oxide to passivate the surface. A layer of sealant is deposited on the substrate in a vacuum to seal the surface.