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.

A drilling machinery orientation apparatus, including an orientation device permanently affixed to, and integral with a structure of, a drilling machine at a point of integration. The orientation device comprises orientation means capable of determining at least an azimuth of a drill rod of the drilling machine prior to drilling a drill hole and determining a change in the azimuth of the drill rod when drilling the drill hole.

Techniques and devices for optical sensing of rotation based on measurements and sensing of optical polarization or changes in optical polarization due to rotation without using optical interferometry. In implementations, a device for optical sensing of rotation can include a detection device that includes: (1) a beam splitter that splits the optical output into four optical beams; (2) four detection modules that receive the four optical beams, respectively, to obtain measurements of four different optical Stokes parameters from the four optical beams, respectively, and (3) a processing unit that processes the measurements of four different optical Stokes parameters to determine a rotation angle of a state of polarization of the optical output and a differential phase shift between the first and the second optical beams caused by a rotation experienced by the optical loop.

A fiber-optic measurement device (10) includes a SAGNAC ring interferometer (20) having a proper frequency f.sub.p, a detector (14) and a modulation chain (30) generating a phase-shift modulation φ.sub.m(t) between the two counter-propagating waves (24, 25) propagating in the ring interferometer. The device aims to reduce measurement faults due to the linearity defects in the modulation chain of such a measurement device with optical fiber. For this reason, the fiber-optic measurement device reduces the amplitude of the phase-shift modulation φ.sub.m(t) which is the sum of a first biasing phase-shift modulation component φ.sub.b1(t) and a first counter-reaction phase-shift modulation component φ.sub.cr1(t), the phase-shift modulation φ.sub.m(t) falling or rising by twice the amplitude of the first biasing phase-shift modulation component φ.sub.b1(t). A rate gyro including such a measurement device and an inertial stabilization or navigation unit including at least one such rate gyro are also described.

Waveguide includes fork with first and second bifurcated ends coupled to loop section and separated by angle determined based on velocities of portions of quantum mechanical wavefunction of atoms traveling above waveguide. Waveguide propagates blue-detuned laser having first evanescent field that repels atoms away from waveguide and red-detuned laser having second evanescent field that attracts atoms toward waveguide, together creating potential minimum/well. Laser cooling atoms, causing atoms positioned in potential minimum/well to move toward first fork section following potential minimum/well. Atomic state initialization section initializes atomic states of atoms to known ground-state configuration. Beam splitter section splits quantum mechanical waveform of each atom above surface of diverging waveguide into first portion at first velocity that travels into first end of first fork section into first loop section and second portion at second velocity that travels into second end of first fork section into first loop section.

A novel and useful electronic gyroscope exploits the Sagnac resulting in a detectable phase or frequency shift when an electromagnetic wave travels inside a rotating medium. These shifts in phase or frequency are measured and used to determine the angular velocity of the rotating medium. Three such media can be positioned in mutually perpendicular planes to detect 3D rotational movement. At least one loop acts as an RF transmission media that accommodates simultaneous bidirectional propagation of RF signals while being capable of separating between signals counter propagating in two opposite directions through the use of a switching matrix. A switching matrix and loop buffer function to sample pulses, amplify them, and reinject them back into one of the loops. A time measurement unit functions to detect the time difference between the counter propagating pulses which is used to calculate the rotation rate of the loop.

Systems and methods are provided to reduce at least one differential harmonics of a resonance tracking modulation in a resonant fiber optic gyroscope (RFOG). The fundamental frequency of the resonance tracking modulation of each of the clockwise and counter clockwise optical signals is substantially identical; however, the amplitude and phase of the Nth harmonic of a clockwise (CW) resonance tracking modulation and the Nth harmonic of a clockwise (CCW) resonance tracking modulation may differ due to non-linearities in the RFOG. Embodiments of the invention diminish, e.g., reduce to zero such vectoral difference. Differential harmonics may be generated at one or more harmonics.

In one embodiment of a superluminescent diode, a first diode adapted on a semiconductor die is to be forward-biased to output optical energy in response to a bias signal, and a second diode adapted on the semiconductor die is to be reverse-biased, the second diode to receive and absorb back propagating optical energy from the first diode and output a measure of the back propagating optical energy as an absorber feedback current. A comparator may be configured to compare the absorber feedback current to a reference current and output a comparison signal, and a driver control circuit coupled to the comparator may provide the bias signal based at least in part on the comparison signal. Other embodiments are described and claimed.

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.

A digital to analog converter for fiber optic gyroscope is disclosed. The digital to analog converter for fiber optic gyroscope includes a random unit generating a random number signal, a plurality of encoding units coupled with the random unit, a plurality of control units respectively one to one coupled with the plurality of encoding units, a current source array coupled with the plurality of control units, and an output load electrically connected to the current source array. Each of the plurality of encoding units converts a plurality of digital signals to a plurality of spin signals according to the random number signal. Each of the plurality of control units converts the plurality of spin signals to a plurality of logic signals. The current source array generates a total current according to the plurality of logic signals. The total current passes through the output load and forms an analog signal.