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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
2.
MITIGATING BIAS INSTABILITIES IN OPTICAL GYROSCOPES
One or more phase modulators in an optical gyroscope operate on two counterpropagating 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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G01C 19/58 - Turn-sensitive devices without moving masses
G01C 19/60 - Electronic or nuclear magnetic resonance gyrometers
G01C 19/62 - Electronic or nuclear magnetic resonance gyrometers with optical pumping
Aspects of the present disclosure are directed to introducing structural modifications in a waveguide-based optical structure in order to more tightly pack adjacent waveguide turns in the optical structure. The optical structure can be used as the rotational sensing element of an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit. Increasing number of turns of a waveguide-based gyroscope coil increases total waveguide length as well as enclosed area of the gyroscope loop, which translates to increased sensitivity to rotational measurement. The structural modifications can be in the form of air-gaps or fluid-filled or metal-filled gaps, or various types of sub-wavelength structures (like gratings or photonic crystals).
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/122 - Basic optical elements, e.g. light-guiding paths
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
6.
INTEGRATED PHOTONICS CHIP WITH ELECTRO-OPTIC MATERIAL BASED WAVEGUIDE COMPONENTS
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.
G01C 19/64 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
7.
PROCESS FLOW WITH PRE-BIASED MASK AND WET ETCHING FOR SMOOTH SIDEWALLS IN SILICON NITRIDE WAVEGUIDES
Aspects of the present disclosure are directed to process flow to fabricate a waveguide structure with a silicon nitride core having atomic-level smooth sidewalls achieved by wet etching instead of the conventional dry etching process. A mask is pre-biased to account for lateral etching during the wet-etching steps.
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 0.1º/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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
11.
SILICON NITRIDE WAVEGUIDE BASED INTEGRATED PHOTONICS FRONT-END CHIP FOR OPTICAL GYROSCOPE
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 electrooptic material, or piezo-electric material or can be thermal phase shifters.
H04N 13/239 - Image signal generators using stereoscopic image cameras using two 2D image sensors having a relative position equal to or related to the interocular distance
H04N 13/344 - Displays for viewing with the aid of special glasses or head-mounted displays [HMD] with head-mounted left-right displays
The present disclosure relates to integrated photonics-based optical gyroscopes with silicon nitride (SiN) waveguide-based microresonators. SiN microresonators are fabricated either on a fused silica platform or on a silicon substrate with oxide cladding. A narrow linewidth high-Q laser is hybridly integrated on a silicon photonics platform. The laser is tuned with a first SiN microresonator, and the rotational sensing component of the gyroscope comprises another SiN microresonator. The silicon photonics front-end chip has components for a balanced detection scheme to cancel noise in the optical signal coming back from the rotational sensing component.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
14.
STRUCTURES FOR INTEGRATED SILICON PHOTONICS OPTICAL GYROSCOPES
Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.
Aspects of the present disclosure are directed to structural modifications introduced in a waveguide structure in order to more tightly pack adjacent waveguide turns in an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit. Increasing number of turns of the gyroscope coil increases total waveguide length as well as enclosed area of the gyroscope loop, which translates to increased sensitivity to rotational measurement.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/28 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/122 - Basic optical elements, e.g. light-guiding paths
16.
Silicon nitride waveguide based integrated photonics front-end chip for optical gyroscope
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
17.
Process flow with pre-biased mask and wet etching for smooth sidewalls in silicon nitride waveguides
Aspects of the present disclosure are directed to process flow to fabricate a waveguide structure with a silicon nitride core having atomic-level smooth sidewalls achieved by wet etching instead of the conventional dry etching process. A mask is pre-biased to account for lateral etching during the wet-etching steps.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/42 - Coupling light guides with opto-electronic elements
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
09 - Scientific and electric apparatus and instruments
Goods & Services
Gyroscopes; Inertial measurement units comprising magnetometers; Inertial measurement units comprising accelerometers and gyroscope for use in navigation and guidance systems
19.
Process flow for fabricating integrated photonics optical gyroscopes
Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
20.
Integration of photonics optical gyroscopes with micro-electro-mechanical sensors
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
Aspects of the present disclosure are directed to fabrication of large-footprint chips having integrated photonic components comprising low-loss optical waveguides. The large footprint chips require the use of multiple reticles during fabrication. Stitching adjacent reticle fields seamlessly is accomplished by overlaying into adjacent reticle fields, tapering waveguide ends, and using strategically placed alignment marks in the die.
G02B 6/13 - Integrated optical circuits characterised by the manufacturing method
G01C 19/64 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
22.
SEAMLESS STITCHING FOR MULTI-RETICLE FABRICATION OF INTEGRATED PHOTONICS OPTICAL COMPONENTS
Aspects of the present disclosure are directed to fabrication of large-footprint chips having integrated photonic components comprising low-loss optical waveguides. The large footprint chips require the use of multiple reticles during fabrication. Stitching adjacent reticle fields seamlessly is accomplished by overlaying into adjacent reticle fields, tapering waveguide ends, and using strategically placed alignment marks in the die.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
23.
System architecture for integrated photonics optical gyroscopes
The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a rotation sensing element, which can be a fiber coil or a sensing coil/micro-resonator ring on a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in the fiber coil or the sensing chip, where the sending chip is coupled to the front end chip. Electrical and/or thermal phase modulators are integrated with the integrated photonics chip. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
24.
Ring waveguide based integrated photonics optical gyroscope with balanced detection scheme
The present disclosure relates to integrated photonics-based optical gyroscopes with silicon nitride (SiN) waveguide-based microresonators. SiN microresonators are fabricated either on a fused silica platform or on a silicon substrate with oxide cladding. A narrow linewidth high-Q laser is hybridly integrated on a silicon photonics platform. The laser is tuned with a first SiN microresonator, and the rotational sensing component of the gyroscope comprises another SiN microresonator. The silicon photonics front-end chip has components for a balanced detection scheme to cancel noise in the optical signal coming back from the rotational sensing component.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first silicon nitride (SiN) waveguide layer that constitute a rotation sensing element; and, a second SiN waveguide layer with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two SiN waveguide layers can be stacked together to have a multi-layer configuration vertically 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 to the SiN waveguide platform. The phase shifters can be made of aluminum nitride (AlN) or strontium bismuth titanate (SBT).
The present disclosure relates to integrated photonics-based optical gyroscopes with silicon nitride (SiN) waveguide-based microresonators. SiN microresonators are fabricated either on a fused silica platform or on a silicon substrate with oxide cladding. A narrow linewidth high-Q laser is hybridly integrated on a silicon photonics platform. The laser is tuned with a first SiN microresonator, and the rotational sensing component of the gyroscope comprises another SiN microresonator. The silicon photonics front-end chip has components for a balanced detection scheme to cancel noise in the optical signal coming back from the rotational sensing component.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/27 - Optical coupling means with polarisation selective and adjusting means
27.
Structures for integrated silicon photonics optical gyroscopes with structural modifications at waveguide crossing
Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
Aspects of the present disclosure are directed to process flow to fabricate a waveguide structure with a silicon nitride core having atomic-level smooth sidewalls achieved by wet etching instead of the conventional dry etching process.
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
29.
Process flow for fabricating integrated photonics optical gyroscopes
Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
30.
Process flow with wet etching for smooth sidewalls in silicon nitride waveguides
Aspects of the present disclosure are directed to process flow to fabricate a waveguide structure with a silicon nitride core having atomic-level smooth sidewalls achieved by wet etching instead of the conventional dry etching process.
G02B 6/00 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/42 - Coupling light guides with opto-electronic elements
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
G03F 7/00 - Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printed surfacesMaterials therefor, e.g. comprising photoresistsApparatus specially adapted therefor
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first silicon nitride (SiN) waveguide layer that constitute a rotation sensing element; and, a second SiN waveguide layer with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two SiN waveguide layers can be stacked together to have a multi-layer configuration vertically 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 to the SiN waveguide platform. The phase shifters can be made of lithium niobate or other electro optic material.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
32.
Integration of photonics optical gyroscopes with micro-electro-mechanical sensors
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
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.
Aspects of the present disclosure are directed to structural modifications introduced in a waveguide structure in order to more tightly pack adjacent waveguide turns in an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit. Increasing number of turns of the gyroscope coil increases total waveguide length as well as enclosed area of the gyroscope loop, which translates to increased sensitivity to rotational measurement.
G02F 1/035 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels or Kerr effect in an optical waveguide structure
G02F 1/295 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the position or the direction of light beams, i.e. deflection in an optical waveguide structure
G02B 6/00 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/122 - Basic optical elements, e.g. light-guiding paths
35.
INTEGRATED PHOTONICS OPTICAL GYROSCOPES WITH IMPROVED SENSITIVITY UTILIZING HIGH DENSITY SILICON NITRIDE WAVEGUIDES
Aspects of the present disclosure are directed to structural modifications introduced in a waveguide structure in order to more tightly pack adjacent waveguide turns in an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit. Increasing number of turns of the gyroscope coil increases total waveguide length as well as enclosed area of the gyroscope loop, which translates to increased sensitivity to rotational measurement.
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first straight waveguide to receive incoming light and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing. The gyroscope comprises a first microresonator ring proximate to the first straight waveguide. Light evanescently couples from the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring. The guided beam evanescently couples back from the first microresonator ring to the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to guided beam to counter the propagation loss. In a coupled-ring configurations, the first microresonator ring acts as a loss ring, and optical gain is imparted to a second microresonator ring which acts as a gain ring.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/27 - Optical coupling means with polarisation selective and adjusting means
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
37.
PROCESS FLOW FOR FABRICATING INTEGRATED PHOTONICS OPTICAL GYROSCOPES
Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
G02B 6/122 - Basic optical elements, e.g. light-guiding paths
G02B 6/132 - Integrated optical circuits characterised by the manufacturing method by deposition of thin films
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
38.
Process flow for fabricating integrated photonics optical gyroscopes
Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
39.
Single-layer and multi-layer structures for integrated silicon photonics optical gyroscopes
Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
40.
RING WAVEGUIDE BASED INTEGRATED PHOTONICS OPTICAL GYROSCOPE WITH GAIN TUNING FOR ENHANCED PERFORMANCE
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first straight waveguide to receive incoming light and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing. The gyroscope comprises a first microresonator ring proximate to the first straight waveguide. Light evanescently couples from the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring. The guided beam evanescently couples back from the first microresonator ring to the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to guided beam to counter the propagation loss. In a coupled-ring configurations, the first microresonator ring acts as a loss ring, and optical gain is imparted to a second microresonator ring which acts as a gain ring.
G02B 6/00 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
41.
Ring waveguide based integrated photonics optical gyroscope with gain tuning for enhanced performance
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first straight waveguide to receive incoming light and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing. The gyroscope comprises a first microresonator ring proximate to the first straight waveguide. Light evanescently couples from the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring. The guided beam evanescently couples back from the first microresonator ring to the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to guided beam to counter the propagation loss. In a coupled-ring configurations, the first microresonator ring acts as a loss ring, and optical gain is imparted to a second microresonator ring which acts as a gain ring.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/27 - Optical coupling means with polarisation selective and adjusting means
G02B 6/126 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
42.
MULTI-LAYER SILICON NITRIDE WAVEGUIDE BASED INTEGRATED PHOTONICS OPTICAL GYROSCOPE CHIP
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first portion with silicon nitride (SiN) waveguides that constitute a rotation sensing element; and, a second portion with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two portions can be stacked together to have a multi-layer configuration vertically 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 to the SiN waveguide platform.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
43.
Multi-layer silicon nitride waveguide based integrated photonics optical gyroscope chip
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first portion with silicon nitride (SiN) waveguides that constitute a rotation sensing element; and, a second portion with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two portions can be stacked together to have a multi-layer configuration vertically 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 to the SiN waveguide platform.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/13 - Integrated optical circuits characterised by the manufacturing method
44.
Integrated photonics optical gyroscopes optimized for autonomous terrestrial and aerial vehicles
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.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/293 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
45.
INTEGRATED PHOTONICS OPTICAL GYROSCOPES OPTIMIZED FOR AUTONOMOUS TERRESTRIAL AND AERIAL VEHICLES
Novel small-footprint integrated photonics optical gyroscopes disclosed herein can provide ARW in the range of 0.05º/√Hr or below (e.g. as low as 0.02º/√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 1.5º/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.
H04N 5/232 - Devices for controlling television cameras, e.g. remote control
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
H01L 21/50 - Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the groups or
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
H01L 33/00 - SEMICONDUCTOR DEVICES NOT COVERED BY CLASS - Details thereof
46.
SYSTEM ARCHITECTURE FOR INTEGRATED PHOTONICS OPTICAL GYROSCOPES
The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in a fiber coil or a sensing chip having a waveguide coil or ring resonator, where the sending chip is coupled to the front end chip. Strip waveguides are designed to primarily select TE mode over TM mode when laser light is coupled into the integrated photonics chip. A plurality of mode-selective filters, based on multi-mode interference (MMI) filter, a serpentine structure, or other types of waveguide-based mode-selective structure, are introduced in the system architecture. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
47.
SINGLE-LAYER AND MULTI-LAYER STRUCTURES FOR INTEGRATED SILICON PHOTONICS OPTICAL GYROSCOPES
Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of- the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
48.
System architecture for integrated photonics optical gyroscopes
The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in a fiber coil or a sensing chip having a waveguide coil or ring resonator, where the sending chip is coupled to the front end chip. Strip waveguides are designed to primarily select TE mode over TM mode when laser light is coupled into the integrated photonics chip. A plurality of mode-selective filters, based on multi-mode interference (MMI) filter, a serpentine structure, or other types of waveguide-based mode-selective structure, are introduced in the system architecture. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
49.
Single-layer and multi-layer structures for integrated silicon photonics optical gyroscopes
Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
50.
System architecture for integrated photonics optical gyroscopes
The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in a fiber coil or a sensing chip having a waveguide coil or ring resonator, where the sending chip is coupled to the front end chip. Strip waveguides are designed to primarily select TE mode over TM mode when laser light is coupled into the integrated photonics chip. A plurality of mode-selective filters, based on multi-mode interference (MMI) filter, a serpentine structure, or other types of waveguide-based mode-selective structure, are introduced in the system architecture. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.
G01C 19/72 - Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
09 - Scientific and electric apparatus and instruments
42 - Scientific, technological and industrial services, research and design
Goods & Services
Gyroscopes; Inertial measurement units; Inertial measurement units comprising accelerometers and gyroscope for use in navigation and guidance; Electronic navigational and positioning apparatus and instruments Design, development, and consulting services related thereto in the field of silicon photonics sensors, fiber optic equipment, navigational and positioning apparatus and instruments, and next generation navigation systems that utilize cellular signals, satellite signals, and wireless internet signals
