Abstract: A method for absolute phase measurement for complex coherence coefficient of an object comprises: firstly, processing fringe data measured by interferometry on any aperture pairs of an equivalent pupil plane of an optical imaging system to obtain an interference term and envelope and extreme values thereof; secondly, selecting extreme value A of light intensity from an interval of relatively stable extreme values change on one side of a curve envelope with zero optical path difference, and selecting two extreme values B and C of light intensity closest to extreme value A on other side of the curve envelope with zero optical path difference, where B>A?C or C>A?B; thirdly, counting number of fringe periods between A and C or A and B; and fourthly, according to the number of fringe periods, selecting a formula to calculate absolute phase of complex coherence coefficient of the object.

Abstract: An optical filter twice filters an optical signal. The optical filter includes a first optical waveguide, an elliptical optical resonator, and a second optical waveguide. The optical signal is coupled from an input/output port of the optical filter which is a port of the first optical waveguide. A portion of the optical signal is coupled through and filtered by the elliptical optical resonator. The filtered optical signal is emitted from another port of the optical filter which is a port of the second optical waveguide. A reflector reflects the filtered optical signal back into the other port. The filtered optical signal is coupled through and filtered by the elliptical optical resonator to the input/output port. A twice filtered optical signal is emitted from the input/output port.

Abstract: The present application discloses a fiber optic sensor and a measurement method, apparatus, and storage medium. By performing, based on the microwave signal, intensity modulation on the optical signal, then inputting the modulated optical signal into the fiber optic containing the weak reflection grating array, a reflected signal is obtained. Thereafter by performing dispersion compensation on the amplified partial reflected signal, and based on the dispersion-compensated reflected signal and the non-dispersion-compensated reflected signal, the change amounts respectively corresponding to positions in the fiber optic containing the weak reflection grating array are determined.

Abstract: A method and system for inspecting polarization in a fibered optical path. The method being executed by a computer-implemented system comprising a controller and at least one detector communicatively coupled to the controller, the computer-implemented system being operatively connected to the fibered optical path, including: causing a laser to emit at least one optical pulse into the fibered optical path; detecting a plurality of reflected optical signals from the fibered optical path; determining a plurality of experimental correlation values based on the plurality of reflected optical signals and a reference signal function; and in response to a given experimental correlation value of the plurality of experimental correlation values being less than a threshold, identifying a mechanical disturbance caused by birefringence in the fibered optical path, the mechanical disturbance being located at a location of the plurality of locations corresponding to the given experimental correlation value.

Abstract: A phase modulation signal generating device for a fiber-optic gyroscope includes a sine wave generating part and a superimposing part. The sine wave generating part generates a fundamental sine wave of an odd-order frequency (v=(2n+1)ve, where n=0, 1, 2, . . . ) of the eigenfrequency (ve) of the fiber-optic coil and a higher-order sine wave of an odd-order harmonic frequency ((2m+1) v, where m=1, 2, 3, . . . ) of the odd-order frequency (v). The superimposing part superimposes the fundamental sine wave and higher-order sine wave generated by the sine wave generating part at a ratio using a modulation index optimized according to a noise target to be minimized and outputs the resultant signal as a phase modulation signal.

Abstract: There is provided a method of calculating a temperature corrected sample position in an interferometric microscope, the method comprising projecting an autofocus beam onto the sample location to form a reflected ring of radiation, detecting an uncalibrated radius. R, of a peak of the annulus of the reflected ring which indicates an uncalibrated sample position, detecting one or more of the width of the annulus or an intensity of the annulus and calculating a calibrated radius Rnorm using at least one of the width of the annulus or the intensity of the annulus to determine the temperature dependent corrected sample position.

Abstract: An object of the present invention is to provide an optical fiber testing device and an optical fiber testing method capable of acquiring both unidirectional crosstalk and bidirectional crosstalk of an uncoupled multicore fiber in a short time and with a little man-hour.

Abstract: A boroscope guide fixture is provided and includes a boroscope, a first section disposed about the boroscope and including first expandable components, first elastics constraining the first expandable components and first concave ends, second sections disposed about the boroscope and third sections. The second sections respectively include second expandable components, second elastics constraining the second expandable components, first convex ends to register with the first concave ends and second concave ends. The third sections are movably affixed to the boroscope and respectively include second convex ends to register with the second concave ends. The boroscope is operable to draw the third sections toward the second sections whereupon registration of the second convex and concave ends expands the second expandable components against the second elastics and registration of the first convex and concave ends expands the first expandable components against the first elastics.

Abstract: An open resonator capable of measuring dielectric characteristic of a sample with high accuracy by removing unnecessary higher-order mode resonance. The open resonator includes: a first spherical reflection mirror having a first reflection spherical surface; and a second spherical reflection mirror having a second reflection spherical surface arranged to face the first reflection spherical surface. At least one of diameters of opening surfaces of the first reflection spherical surface and the second reflection spherical surface exposed to a space between the first reflection spherical surface and the second reflection spherical surface is equal to or less than a half of a distance between the first reflection spherical surface and the second reflection spherical surface.

Abstract: A multi-channel SMI sensor includes an emitter configured to emit light having different polarizations and a polarization-selective lens for directing light having different polarizations towards different locations. The multi-channel SMI sensor is configured to measure physical phenomena at two different locations with a small footprint.

Abstract: A wafer inspection apparatus includes: a stage configured such that a wafer is arranged on the stage; an optical apparatus configured to align the wafer on the stage and generate an optical intensity image including an optical intensity profile; a focus adjusting unit configured to align light incident onto the wafer to be in-focus; and an image processor configured to integrate the optical intensity image with vertical level data of the in-focus to generate and analyze a three-dimensional (3D) image.

Abstract: This work relates to a geometric-phase metasurface combined with a fluidic circuit for tuning the properties of the metasurface (especially its diffraction efficiency). We consider two aspects of particular interest: A) Dynamic on-demand diffractive optics (operating in transmission), both as optical elements for altering incident light, and as sensors of the refractive index of a fluid; and B) Transparent, reflective displays. Here the display itself is transmissive, but operates in reflection. One application of dynamic on-demand diffractive optics is to replace the lens array often needed in light field displays.

Abstract: One example system includes a first light detection and ranging (LIDAR) device that scans a first field-of-view defined by a first range of pointing directions associated with the first LIDAR device. The system also includes a second LIDAR device that scans a second FOV defined by a second range of pointing directions associated with the second LIDAR device. The second FOV at least partially overlaps the first FOV. The system also includes a first controller that adjusts a first pointing direction of the first LIDAR device. The system also includes a second controller that adjusts a second pointing direction of the second LIDAR device synchronously with the adjustment of the first pointing direction of the first LIDAR device.

Abstract: The distance measuring assembly is a two camera system featuring three axis controls connected such that a first camera has pan and tilt control and the second camera shares the pan and tilt of the first camera and further has an independent pan or tilt. The second camera is attached to the first camera by a dogleg servo horn providing an offset to align the optical axis of the first and second camera. The assembly is adapted to find a target object by locating it and aligning an optical axis of each camera with the target object, and using the angular offset calculated by the axis controllers to triangulate the position of the target object.

Abstract: An apparatus may include a platen, a light source system and a receiver system. The light source system may at least a first light-emitting component and at least a first light guide component. The first light guide component may be configured to transmit light from the first light-emitting component towards a target object in contact with a first area of the platen. The receiver system may include at least two receiver stack portions. A first receiver stack portion may reside proximate a first side of a first portion of the first light guide component and a second receiver stack portion may reside proximate a second side of the first portion of the first light guide component. The receiver system may be configured to detect acoustic waves corresponding to a photoacoustic response of the target object to light emitted by the light source system.

Abstract: A method of rapid coherent synthetic wavelength interferometric absolute distance measurement includes receiving, from an optical system, an image from an object scene of at least two distinct wavelengths of light, each wavelength's light source having a coherence length greater than a desired ambiguity length of the absolute distance measurement, and whose synthetic wavelength in combination provides the desired ambiguity length of the absolute distance measurement. A phase-based approach, a magnitude-based approach, or an envelope of the magnitude-based approach can be taken to determine an interference between light returning from the object scene and light traversing a separate reference arm path of the optical system and calculate an optical distance to an object in the object scene.

Abstract: The present disclosure provides a dispersion measurement device and method based on a Franson second-order quantum interference technology. The device includes: an energy-time entangled twin-photon source configured to generate a plurality of optical signals, where the optical signals each include a signal photon and an idle photon; a polarization splitter configured to split the signal photon and the idle photon, and enable the signal photon to pass through a to-be-measured dispersive medium, such that a correlation time processing module records, under a width of a coincidence measurement integration window, first time of the idle photon arriving at a first single-photon detector, and second time of the signal photon arriving at a second single-photon detector, and obtains a twin-photon conference time width based on the first time and the second time; and a processing module.

Abstract: A method for measuring a response from an optical fiber providing distributed back reflections using a system comprising an optical source comprising a laser, an optical receiver and a processing unit is disclosed. The method comprises generating an interrogation signal and an optical local oscillator using the optical source, the interrogation signal being represented by an interrogation phasor and the optical local oscillator being represented by a local oscillator phasor; transmitting the interrogation signal into the optical fiber; and mixing the optical local oscillator with reflected light from the optical fiber and detecting a mixing product with the optical receiver to achieve a receiver output signal.

Abstract: Methods, devices, systems, and computer program products for estimating object reflectivity in a light detection and ranging (LIDAR) system are disclosed. The method, for example, includes receiving LIDAR data for a plurality of LIDAR scan cycles. The method also includes generating a dataset from the LIDAR data by accumulating the recorded return signals over the plurality of scan cycles. A data feature associated with an object is identified in the dataset, and one or more parameters of the data feature are identified. An estimated reflectivity of the object may then be determined based on the one or more parameters.

Abstract: A LIDAR system including a MEMS scanning device is disclosed. The LIDAR system includes a light source, a light deflector, a sensor, and a processor. The light deflector deflects light from the light source or light received from an environment outside a vehicle in which the LIDAR system is installed. The sensor detects the light received from the light source or the environment. The processor determines a distance of one or more objects in the environment from the vehicle based on the signals from the sensor. The light deflector includes one or more actuators, which include one or more actuating arms. Connectors connect the actuating arms to an MEMS mirror or other deflector. The actuating arms move when subjected to an electrical field in the form of a voltage or current. Movement of the actuating arms causes movement of the MEMS mirror or deflector causing it to deflect light.