A microelectromechanical systems (MEMS) device comprises an optical directional coupler comprising: a first waveguide having a first and a second end, wherein a light beam is introduced into the first end; a second waveguide having a third and a fourth end, wherein the light beam is evanescently coupled between the two waveguides in the central region; a first photodetector to detect first optical power in the light beam at the second end; and a second photodetector to detect second optical power in the light beam at the fourth end; a vibrating proof mass adjacent to the coupler in a first direction from the coupler, wherein when inertial forces are applied to the MEMS device in a second direction, the proof mass moves in the first direction; a processor to determine the displacement of the proof mass from the coupler as a function of the first and the second optical power.

Microelectromechanical system (MEMS) device readout with optical directional coupler

An iterative method for determining scattering coefficients of the cavity of a laser gyro in operation supporting two counter-propagating modes, comprises steps of: determining a set of variables dependent on characteristic physical quantities of the laser gyro, one reference variable per dependency relationship being selected from the variables; measuring values of the characteristic physical quantities of the laser gyro in operation; determining measured values of the variables; estimating, via an iterative method, estimated values of the coefficients minimising a discrepancy between the measured values of the reference variables and estimated values of the reference variables, which are estimated from the values of the coefficients and the measured values of the variables other than the reference variables; and determining estimated values of the scattering coefficients from the estimated values of the coefficients.

Method for estimating scattering coefficients of a laser gyro in operation and associated gyroscopic system

A passive ring interferometer sensor includes an electromagnetic ring path configured to receive a pair of electromagnetic waves from an electromagnetic radiation source and to direct the waves to be counter-propagating within the ring path toward respective ends of the path. A combination junction receives the waves from the respective ends and combines the waves to be co-propagating within a coupling path. Polarization elements are configured to set the waves to be mutually co-polarized within the electromagnetic ring path and to be mutually cross-polarized within the coupling path. A detector is configured to receive the mutually cross-polarized waves from the coupling path and to detect second-order coherence. Embodiments can sense rotation rate as fiber-optic gyroscopes or serve as other types of sensors such as gravitational wave sensors. Embodiments may have greatly increased unambiguous range and decreased sensitivity to any centroid wavelength shift.

Second-order passive ring interferometer sensor and method

The invention is applicable to the technical field of radio frequency microwaves, and provides a silicon-based micro coaxial structure, which comprises an upper-layer silicon wafer, a middle-layer silicon wafer and a lower-layer silicon wafer, wherein a first groove is formed in the upper-layer silicon wafer, and the first groove is cut off at a position which is a first preset distance away fromthe outer edge of the upper-layer silicon wafer; a plurality of first through holes penetrating through the upper surface and the lower surface are formed in the periphery of the closed end of the first groove; the middle-layer silicon wafer comprises a U-shaped silicon wafer, a core silicon wafer, a plurality of left support beam silicon wafers and a plurality of right support beam silicon wafers, and is provided with a plurality of second through holes penetrating through the upper surface and the lower surface; the lower-layer silicon wafer is provided with a switching groove, a third groove, a bonding pad, a switching support structure, a third through hole, a fourth through hole and a plurality of fifth through holes. The upper-layer silicon wafer, the middle-layer silicon wafer and the lower-layer silicon wafer are bonded through a metal layer in a preset area, so that the first groove, the U-shaped silicon wafer and the third groove form a cavity which surrounds the core siliconwafer and is filled with air, the cavity and the core silicon wafer form a coaxial structure, the transmission performance is good, and integration is easy.

Silicon-based micro coaxial structure

The invention discloses an ultrasonic measurement device for realizing optical path and polarization state regulation and control based on an SAGNAC principle. The device comprises a light source, a sample probe, a circulator, a first polarization controller, a second polarization controller, a third polarization controller, a fourth polarization controller, a fifth polarization controller, a first unpolarized 1*2 coupler, a second unpolarized 1*2 coupler, a photoelectric detection device, a wavelength selector and a light path selector. Light emitted by the light source firstly passes througha wavelength selector, the first polarization controller and the circulator and is divided into two paths with different lengths through a first non-polarization coupler, one path is CW light in a clockwise direction, and the other path is CCW light in an anticlockwise direction. Compared with the prior art, the method for achieving non-contact ultrasonic detection through an SAGNAC effect is simple in structure, low in cost, small in size, high in sensitivity and wide in application range.

Ultrasonic measurement device for realizing optical path and polarization state regulation and control based on SAGNAC principle

A radio frequency based electronic gyroscope function that may be incorporated in its entirety on a monolithic integrated circuit (IC). The detection and measurement of movement in a particular plane is based on the Sagnac effect as it applies to a radio frequency signal that propagates in two different directions in a loop that may be subject to rotational perturbation. In one embodiment, three mutually perpendicular loops that are incorporated into the same integrated circuit and are used to detect and measure movement in three planes (roll, pitch and yaw) thereby allowing a signal processing unit to quantify a general three dimensional movement. The gyroscope can be incorporated into an IC that is used in portable device, such as a mobile handset, to provide it with inertial navigation and movement detection and measurement capabilities.

Daryl Wade Barry

Papers

Sagnac effect based radio frequency electronic gyroscope incorporated in CMOS integrated circuit