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.

The described embodiments relate to a photonic integrated circuit (PIC) for use in a fiber optic gyroscope (FOG). Some embodiments describe a PIC with connectors for coupling to external components such as a light source, a photodetector and a fiber coil, with beamsplitting devices (e.g., couplers), waveguide and other photonic components integrated on the PIC. Some embodiments describe a hybrid PIC (HPIC) with the PIC, light source and photodetector attached to a common submount, and with connectors for coupling to a fiber coil. Other embodiments describe an extended PIC (EPIC) that integrates the PIC components, the light source, the photodetector, and other components (e.g., a wavemeter) on a common substrate. The described embodiments may also include a detection/feedback circuit that provides control signals and other parameters to the PIC, HPIC, or EPIC, and receives output signals from the PIC, HPIC, or EPIC.

The present disclosure provides a LIDAR-gyroscope chip assembly (also referred to as GIDAR) for autonomous vehicle navigation application. The chip assembly includes a silicon substrate, a LIDAR chip assembly disposed on the substrate, and a gyroscope disposed on the substrate in order to form one integrated sensing chip performing both inertial and LIDAR sensing. The single chip integration can be improved by using silicon nitride to form the LIDAR chip assembly components and the components of the gyroscope. Incorporating chip-based inertial measurement unit (IMU) and LIDAR system onto a single chip, leads to power, weight, and size reduction for autonomous vehicles navigation applications, especially for small drones and small robots where the vehicle is limited to size and power consumption. Due to the full integration of all elements onto one chip, the devices as described herein will be less sensitive to environmental perturbations such as shocks and vibrations compared to conventional devices.

A system for stabilizing a scale factor associated with an optic rotation sensor comprises an optic rotation sensor that generates an optic signal in response to a rotation of the optic rotation sensor. A sensor detection system produces a rotation signal as a function of the optic signal and rotation of the optic rotation sensor. A first waveguide guides a portion of the optic signal for an interaction length, and produces a first processed optic signal. A second waveguide receives a portion of the optic signal from first waveguide through evanescent coupling, and produces a second processed optic signal. A wavemeter detector receives the optic signals and measures the effective interferometric wavelength (EIW) of the light based on the optic signals. A scale factor correction system receives the rotation signal and the EIW, and measures the correct rotation signal by processing the rotation signal and the EIW.

The described embodiments relate to a photonic integrated circuit (PIC) for use in a fiber optic gyroscope (FOG). Some embodiments describe a PIC with connectors for coupling to external components such as a light source, a photodetector and a fiber coil, with beamsplitting devices (e.g., couplers), waveguide and other photonic components integrated on the PIC. Some embodiments describe a hybrid PIC (HPIC) with the PIC, light source and photodetector attached to a common submount, and with connectors for coupling to a fiber coil. Other embodiments describe an extended PIC (EPIC) that integrates the PIC components, the light source, the photodetector, and other components (e.g., a wavemeter) on a common substrate. The described embodiments may also include a detection/feedback circuit that provides control signals and other parameters to the PIC, HPIC, or EPIC, and receives output signals from the PIC, HPIC, or EPIC.

This invention describes a gyroscope using a fiber coil which is coupled using integrated on-chip 33 and 22 couplers in coplanar as well as non-coplanar (NCP) configuration along with photodetectors, light sources, and processing electronics using Si, SOI, and InGaAs-on-Si, and other substrates. In one embodiment, a high sensitivity gyroscope using a combination of 22 and 33 waveguide couplers is described. The signals from three photodetectors can be used to generate feedback signals to produce high sensitivity. Still in another embodiment, usage of multiple quantum well (MQW) waveguides is illustrated. MQW waveguides can be tuned to achieve phase modulation/correction in couplers.

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.

The drift (/h) for an interferometric fiber optic gyroscope (IFOG) means the variations on the voltage generated versus the zero angular (rotation) rate, while IFOG is not under influence of any angular rate effect. If the drift of an IFOG is predefined, the compensation of the drift can trivially be carried out by a subtraction process. However, with this invention, the necessity of the predefinition of the zero rotation rate voltage of the IFOG which belongs to the primary coil called Gyro Coil herein, is removed because the instantaneous variations on the zero rotation rate voltage of the IFOG can be monitored either periodically or whenever required with help of a secondary coil, called as Monitor Coil, which is able to be switched by a microcontroller controlled-MEMS fiber optic ON/OFF switches. The new configuration of IFOG, to be referred as Dynamical Drift Monitoring-Interferometric Fiber Optic Gyroscope (DDM-IFOG) and the new method presented and implemented in this invention are valid for IFOG having open-loop and closed-loop schemes by engaging the voltage of zeroing the total phase (Feedback Phase plus Sagnac Phase Shift) in the sensing coil instead of directly using the voltage of the demodulation circuit induced by the Sagnac Phase Shift (SPS).

This invention describes a gyroscope using a fiber coil which is coupled using integrated on-chip 33 and 22 couplers in coplanar as well as non-coplanar (NCP) configuration along with photodetectors, light sources, and processing electronics using Si, SOI, and InGaAs-on-Si, and other substrates. In one embodiment, a high sensitivity gyroscope using a combination of 22 and 33 waveguide couplers is described. The signals from three photodetectors can be used to generate feedback signals to produce high sensitivity. Still in another embodiment, usage of multiple quantum well (MQW) waveguides is illustrated. MQW waveguides can be tuned to achieve phase modulation/correction in couplers.

The invention relates to an integrated optical coupler (1) comprising a substrate (3), at least two planar waveguides (4), which are arranged on or in the substrate (3) and consist of a material having a virtually isotropic refractive index (anisotropy of the refractive index of less than 10.sup.6), and al least three monomode fibers (8, 9, 10) coupled to the planar waveguides (4). One of the monomode fibers (8) is a polarization-maintaining fiber. A fiber optic system according to the invention comprises an integrated optical coupler (1) according to the invention, a light source (21) that is suitable for generating light beams, and a first pigtail fiber (22), which is connected at one end to the light source (21) and at the other end to the polarization-maintaining fiber (8) of the integrated optical coupler (1).