Abstract: One or more phase modulators in an optical gyroscope operate on two counter-propagating beams to introduce a phase shift between the beams before the beams are interferometrically combined to generate a rotation signal. A signal generator generates first and second modulation frequencies to drive the phase modulators. The first modulation frequency in isolation biases the rotation signal at an operating point sensitive to rotation, and the second modulation frequency in isolation biases the rotation signal at an operating point insensitive to rotation. One or more control integrated circuits (ICs) isolate a first portion of the rotation signal associated with the first modulation frequency and a second portion of the rotation signal associated with the second modulation frequency. The control ICs determine a difference between the first and second portions of the rotation signal to remove one or more bias instabilities from the first portion of the rotation signal.

Abstract: One or more phase modulators in an optical gyroscope operate on two counter-propagating beams to introduce a phase shift between the beams before the beams are interferometrically combined to generate a rotation signal. A signal generator generates first and second modulation frequencies to drive the phase modulators. The first modulation frequency in isolation biases the rotation signal at an operating point sensitive to rotation, and the second modulation frequency in isolation biases the rotation signal at an operating point insensitive to rotation. One or more control integrated circuits (ICs) isolate a first portion of the rotation signal associated with the first modulation frequency and a second portion of the rotation signal associated with the second modulation frequency. The control ICs determine a difference between the first and second portions of the rotation signal to remove one or more bias instabilities from the first portion of the rotation signal.

Abstract: A railway geogrid construction is suitable for use with high speed trains to mitigate the increased impact of Rayleigh waves generated at high speed and/or over soft subgrades. The construction includes a track bed which defines a track located on a track plane, a mass of particulate material such as an aggregate forming a layer located beneath the track plane, and a geogrid located in and/or below the particulate mass in a geogrid plane substantially parallel to the track plane where the average distance between the track plane and geogrid plane, measured perpendicular to both, is greater than 0.65 metres.

Abstract: The present disclosure relates to integration of integrated photonics-based optical gyroscopes and fiber-based optical gyroscopes into portable apparatuses that may include compass features. Novel small-footprint modularized fully integrated photonics optical gyroscopes are used for non-critical axes. However, for at least one critical axis, a fiber-optic gyroscope can be used to provide bias stability below 0.1°/Hr, which is directly correlated to predicting positional accuracy in the centimeter range. The positional accuracy results from the compassing ability of the gyroscope (referred to as gyrocompass) to calculate direction of heading using the earth's rotation.

Abstract: An integrated photonics optical gyroscope front-end chip is fabricated on a waveguide platform made of electro-optic materials. The front-end chip launches light into and receive light from the rotation sensing element, that can be a fiber spool or a waveguide coil/microresonator ring. The waveguide coil/microresonator ring can be made of the same electro-optic material platform or a different material platform. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than the electro-optic material and can be hybridly integrated or otherwise coupled to the waveguide platform. Additional phase shifters can be made of piezo-electric material or can be thermal phase shifters.

Abstract: The present disclosure relates to integration of integrated photonics-based optical gyroscopes and fiber-based optical gyroscopes into portable apparatuses that may include compass features. Novel small-footprint modularized fully integrated photonics optical gyroscopes are used for non-critical axes. However, for at least one critical axis, a fiber-optic gyroscope can be used to provide bias stability below 0.1°/Hr, which is directly correlated to predicting positional accuracy in the centimeter range. The positional accuracy results from the compassing ability of the gyroscope (referred to as gyrocompass) to calculate direction of heading using the earth's rotation.

Abstract: The present disclosure relates to integration of integrated photonics-based optical gyroscopes and fiber-based optical gyroscopes into portable apparatuses that may include compass features. Novel small-footprint modularized fully integrated photonics optical gyroscopes are used for non-critical axes. However, for at least one critical axis, a fiber-optic gyroscope can be used to provide bias stability below 0.1°/Hr, which is directly correlated to predicting positional accuracy in the centimeter range. The positional accuracy results from the compassing ability of the gyroscope (referred to as gyrocompass) to calculate direction of heading using the earth's rotation.

Abstract: An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element, that can be a fiber spool. The SiN waveguide-based components can be distributed between multiple layers that are stacked together to have a multi-layer configuration vertically and evanescently coupled with each other. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than SiN and can be hybridly integrated or otherwise coupled to the SiN waveguide platform. The phase shifters can be made of electro-optic material, or piezo-electric material or can be thermal phase shifters.

Abstract: Novel small-footprint integrated photonics optical gyroscopes disclosed herein can provide ARW in the range of 0.05°/?Hr or below (e.g. as low as 0.02°/?Hr), which makes them comparable to fiber optic gyroscopes (FOGs) in terms of performance, at a much lower cost. The low bias stability value in the integrated photonics optical gyroscope corresponds to a low bias estimation error (in the range of 1.5°/Hr or even lower) that is crucial for safety-critical applications, such as calculating heading for autonomous vehicles, drones, aircrafts etc. The integrated photonics optical gyroscopes may be co-packaged with mechanical gyroscopes into a hybrid inertial measurement unit (IMU) to provide high-precision angular measurement for one or more axes.

Abstract: An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element, that can be a fiber spool. The SiN waveguide-based components can be distributed between multiple layers that are stacked together to have a multi-layer configuration vertically and evanescently coupled with each other. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than SiN and can be hybridly integrated or otherwise coupled to the SiN waveguide platform. The phase shifters can be made of electro-optic material, or piezo-electric material or can be thermal phase shifters.

Abstract: Novel small-footprint integrated photonics optical gyroscopes disclosed herein can provide ARW in the range of 0.05°/?Hr or below (e.g. as low as 0.02°/?Hr), which makes them comparable to fiber optic gyroscopes (FOGs) in terms of performance, at a much lower cost. The low bias stability value in the integrated photonics optical gyroscope corresponds to a low bias estimation error (in the range of 1.5°/Hr or even lower) that is crucial for safety-critical applications, such as calculating heading for autonomous vehicles, drones, aircrafts etc. The integrated photonics optical gyroscopes may be co-packaged with mechanical gyroscopes into a hybrid inertial measurement unit (IMU) to provide high-precision angular measurement for one or more axes.

Abstract: Aspects of the present disclosure are directed to monolithically integrating an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit with a MEMS accelerometer on the same die. The accelerometer can be controlled by electronic circuitry that controls the optical gyroscope. The optical gyroscope may have a microresonator ring or a multi-turn waveguide coil. Gaps may be introduced between adjacent waveguide turns to reduce cross-talk and improve sensitivity and packing density of the optical gyroscope.

Abstract: Aspects of the present disclosure are directed to monolithically integrating an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit with a MEMS accelerometer on the same die. The accelerometer can be controlled by electronic circuitry that controls the optical gyroscope. The optical gyroscope may have a microresonator ring or a multi-turn waveguide coil. Gaps may be introduced between adjacent waveguide turns to reduce cross-talk and improve sensitivity and packing density of the optical gyroscope.

Abstract: Aspects of the present disclosure are directed to monolithically integrating an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit with a MEMS accelerometer on the same die. The accelerometer can be controlled by electronic circuitry that controls the optical gyroscope. Gaps may be introduced between adjacent waveguide turns to reduce cross-talk and improve sensitivity and packing density of the optical gyroscope.

Abstract: Inertial measurement systems and methods are described. An exemplar inertial measurement system includes: a plurality of inertial sensors each configured to output an inertial sensing signal; a filter module configured to separate the inertial sensing signal of at least one of the plurality of inertial sensors into a low-frequency component and a high-frequency component; a temperature calibration module configured to perform a temperature calibration on the low-frequency component of the inertial sensing signal of the at least one of the plurality of inertial sensors; a noise reduction module configured to perform a noise reduction on the high-frequency component of the inertial sensing signal of the at least one of the plurality of inertial sensors; and a recombination module configured to recombine the calibrated low-frequency component and the noise reduced high-frequency component to form a recombined inertial sensing signal with improved thermal drift performance and noise performance.

Abstract: Communications are facilitated via a mobile internet-enabled connection interface are provided. One apparatus is configured to perform various operations, including performing a first type of security function associated with determining whether an information package is authorized to be received and downloaded to a device other than the apparatus, wherein the information package is associated with updating a functionality of the device; and performing a second type of security function associated with identifying an authorized user of the apparatus.

Abstract: Aspects of the present disclosure are directed to monolithically integrating an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit with a MEMS accelerometer on the same die. The accelerometer can be controlled by electronic circuitry that controls the optical gyroscope. Gaps may be introduced between adjacent waveguide turns to reduce cross-talk and improve sensitivity and packing density of the optical gyroscope.

Abstract: Apparatus, methods and systems facilitating communications via a mobile internet-enabled connection interface are provided. One apparatus is configured to perform various operations, including performing a first type of security function associated with determining whether an information package is authorized to be received and downloaded to a device other than the apparatus, wherein the information package is associated with updating a functionality of the device; and performing a second type of security function associated with identifying an authorized user of the apparatus.

Abstract: There is disclosed a railway geogrid construction suitable for use with high speed trains to mitigate the increased impact of Rayleigh waves generated at high speed and/or over soft subgrades, the construction comprising: a track bed (e.g. having rails for a train) which defines a track located on a track plane; a mass of particulate material (e.g. aggregate) forming a layer located beneath the track plane; and a geogrid located in and/or below the particulate mass in a plane (geogrid plane) substantially parallel to the track plane where the average distance between the track plane and geogrid plane, measured perpendicular to both is greater than 0.65 metres.

Abstract: Novel small-footprint integrated photonics optical gyroscopes disclosed herein can provide ARW in the range of 0.05°/?Hr or below (e.g. as low as 0.02°/?Hr), which makes them comparable to fiber optic gyroscopes (FOGs) in terms of performance, at a much lower cost. The low bias stability value in the integrated photonics optical gyroscope corresponds to a low bias estimation error (in the range of 1.5°/Hr or even lower) that is crucial for safety-critical applications, such as calculating heading for autonomous vehicles, drones, aircrafts etc. The integrated photonics optical gyroscopes may be co-packaged with mechanical gyroscopes into a hybrid inertial measurement unit (IMU) to provide high-precision angular measurement for one or more axes.