276 results about "Optical interferometer" patented technology

Preferred embodiments of the present invention are directed to systems for phase measurement which address the problem of phase noise using combinations of a number of strategies including, but not limited to, common-path interferometry, phase referencing, active stabilization and differential measurement. Embodiment are directed to optical devices for imaging small biological objects with light. These embodiments can be applied to the fields of, for example, cellular physiology and neuroscience. These preferred embodiments are based on principles of phase measurements and imaging technologies. The scientific motivation for using phase measurements and imaging technologies is derived from, for example, cellular biology at the sub-micron level which can include, without limitation, imaging origins of dysplasia, cellular communication, neuronal transmission and implementation of the genetic code. The structure and dynamics of sub-cellular constituents cannot be currently studied in their native state using the existing methods and technologies including, for example, x-ray and neutron scattering. In contrast, light based techniques with nanometer resolution enable the cellular machinery to be studied in its native state. Thus, preferred embodiments of the present invention include systems based on principles of interferometry and/or phase measurements and are used to study cellular physiology. These systems include principles of low coherence interferometry (LCI) using optical interferometers to measure phase, or light scattering spectroscopy (LSS) wherein interference within the cellular components themselves is used, or in the alternative the principles of LCI and LSS can be combined to result in systems of the present invention.

Preferred embodiments of the present invention are directed to systems for phase measurement which address the problem of phase noise using combinations of a number of strategies including, but not limited to, common-path interferometry, phase referencing, active stabilization and differential measurement. Embodiment are directed to optical devices for imaging small biological objects with light. These embodiments can be applied to the fields of, for example, cellular physiology and neuroscience. These preferred embodiments are based on principles of phase measurements and imaging technologies. The scientific motivation for using phase measurements and imaging technologies is derived from, for example, cellular biology at the sub-micron level which can include, without limitation, imaging origins of dysplasia, cellular communication, neuronal transmission and implementation of the genetic code. The structure and dynamics of sub-cellular constituents cannot be currently studied in their native state using the existing methods and technologies including, for example, x-ray and neutron scattering. In contrast, light based techniques with nanometer resolution enable the cellular machinery to be studied in its native state. Thus, preferred embodiments of the present invention include systems based on principles of interferometry and/or phase measurements and are used to study cellular physiology. These systems include principles of low coherence interferometry (LCI) using optical interferometers to measure phase, or light scattering spectroscopy (LSS) wherein interference within the cellular components themselves is used, or in the alternative the principles of LCI and LSS can be combined to result in systems of the present invention.

A system monitors or images a portion of a sample. The system includes an optical interferometer with a measurement arm, a reference arm, and an optical splitter. The arms are coupled to receive light from the optical splitter. One of the arms includes an acousto-optical modulator. The interferometer is configured to interfere light output from the two arms. The system also includes a detector that receives the interfered light and uses the received light to determine a depth-dependent quantity characterizing a portion of the interior of the sample.

A laser welding apparatus includes: a first optical element that coaxially emits, to a welded part, a laser beam emitted from a laser light source and an object beam having a different wavelength from the laser beam; a second optical element that causes the spot diameter of the object beam to be larger than the spot diameter of the laser beam on the welded part; an optical interferometer that emits the object beam to the first optical element, detects through the first optical element the object beam reflected on the welded part, and generates an electric signal based on the detected object beam; and a measuring unit that measures a penetration depth of the welded part based on the electric signal.

Provided are techniques for generating optical vector beams (e.g., radially and azimuthally polarized light) using passive or active phase stable optical interferometry. Techniques may split an input optical beam into at least two output beams, and then couple those beams simultaneously into a passively phase stable optical interferometer. Beam splitting may be achieved by a diffractive optical element and coupling may be achieved by a single refractive optical device (lenses) or by a single mirror device (e.g., parabolic and spherical). The interferometer may provide the ability to manipulate (or transform) the polarization of part of the wavefront of each beam, as well as the ability to manipulate (or transform) the phase of part of the wavefront of each beam, such that the beams when combined have a vector beam polarization state.

For measuring a laser frequency electronic signals can be generated by means of optical interferometers, especially Michelson, Mach-Zehnder and Fabry-Perot interferometers. These signals present profiles with a variation of the laser frequency which are practically identical but shifted in phase by 90°. It is common to generate such phase-shifted signals for frequency measurement in various systems, e.g. by means of a sigmameter, which present, however, disadvantages on account of the great number of the necessary high-quality optical components. The inventive method is based on the analysis of transmission and reflection signals of a Fabry-Perot interferometer (FPI) wherein the signals are obtained from two component beams (PBA and PBB) which are passed through slightly different path lengths within the interferometer. These differences in the length of the optical paths are so selected by different angles of incidence of the component beams into the Fabry-Perot interferometer or by an appropriate shape of the interferometer that the required 90° phase shift is adjusted between the detected intensity signals. From these signals electronic signals can be obtained for detection and also for a rapid correction of the laser frequency.

Real time high speed high resolution hyper-spectral imaging. (a) electromagnetic radiation collimating element (16), collimating electromagnetic radiation (44) emitted by objects (12) in a scene or a sample (14); (b) optical interferometer (18), receiving and dividing collimated object emission beam, generating interference images, and piezoelectrically determining and changing magnitude of optical path difference of divided collimated object emission beam; optical interferometer (18) includes: beam splitter (20′), fixed mirror (22), movable mirror (24), piezoelectric motor (26), displacing movable mirror (24) along axis (60), distance change feedback sensor (28), sensing and measuring change in distance of movable mirror (24) along axis (60), piezoelectric motor controller (30), actuating and controlling piezoelectric motor (26); and thermo-mechanically stable optical interferometer mount (32A); (c) camera optics (34), focusing interference images of each optical path difference; (d) detector (36), recording interference images; processing unit (38), and (f) display (40).

The present invention discloses one kind of spectral-domain optical coherent tomography endoscopic image system for in vivo optical biopsy, and the system includes one fiber optical interferometer, one imaging probe, one detection unit, one image acquiring card and one computer. The detection unit has grating spectrograph for high imaging speed, and the imaging probe has axial axicon lens and inside rotating right angle prism or circularly symmetric beam splitter combined to ensure high transverse resolution in the whole depth range, so as to realize circularly scanning endoscopic imaging. The present invention proposes two embodiments of circularly scanning probe and their corresponding system structures. The present invention may be applied in the optical endoscopic biopsy and analytic study of oral cavity, respiratory tract, gastrointestinal tract, etc.

A real-time, three-dimensional optical coherence tomography system includes an optical interferometer configured to illuminate a target with light and to receive light returned from the target; an optical detection system arranged in an optical path of light from the optical interferometer after being returned from the target, the optical detection system providing output data signals; and a data processing system adapted to communicate with the optical detection system to receive the output data signals. The data processing system includes a parallel processor configured to process the output data signals to provide real-time, three-dimensional optical coherence tomography images of the target.

An airway adapter that comprises a housing and a pressure transducer. The housing comprises a flow path having a first end and a second end, a first pressure port that communicates with the flow path, and a second pressure port that communicates with the flow path. The first pressure port is spaced apart from the second pressure port. The flow restriction is disposed in the flow path between the first and second pressure ports that creates a pressure differential therebetween. The pressure transducer generates a signal that reflects the differential pressure created by the flow restriction between the first and second pressure ports, wherein the pressure transducer comprises an optical interferometer.

A measurement method and apparatus rely upon the coherent optical interference between a reference beam and a diffractionless sensing beam having an optical path length that has been disturbed. The interference pattern can be analyzed to determine a measurement parameter of the disturbance. The diffractionless beam is particularly a Bessel beam. Exemplary optical interferometer types including Mach-Zehnder, Michelson, Sagnac and Fabry-Perot include a Bessel beam generator to generate a diffractionless beam as the sensing optical beam and in some aspects the reference optical beam of the interferometer. The sensing optical beam propagates along a sensing optical beam path in free-space. The reference optical beam path may be a free-space medium or a material medium such as an optical fiber. The sensing optical beam path is subject to a disturbance manifested by the optical interference pattern between the sensing optical beam and the reference optical beam. Parameters of the disturbance, such as motion, acoustics, environmental conditions and others can be determined by analysis of the interference pattern.

Preferred embodiments of the present invention are directed to systems for phase measurement which address the problem of phase noise using combinations of a number of strategies including, but not limited to, common-path interferometry, phase referencing, active stabilization and differential measurement. Embodiment are directed to optical devices for imaging small biological objects with light. These embodiments can be applied to the fields of, for example, cellular physiology and neuroscience. These preferred embodiments are based on principles of phase measurements and imaging technologies. The scientific motivation for using phase measurements and imaging technologies is derived from, for example, cellular biology at the sub-micron level which can include, without limitation, imaging origins of dysplasia, cellular communication, neuronal transmission and implementation of the genetic code. The structure and dynamics of sub-cellular constituents cannot be currently studied in their native state using the existing methods and technologies including, for example, x-ray and neutron scattering. In contrast, light based techniques with nanometer resolution enable the cellular machinery to be studied in its native state. Thus, preferred embodiments of the present invention include systems based on principles of interferometry and/or phase measurements and are used to study cellular physiology. These systems include principles of low coherence interferometry (LCI) using optical interferometers to measure phase, or light scattering spectroscopy (LSS) wherein interference within the cellular components themselves is used, or in the alternative the principles of LCI and LSS can be combined to result in systems of the present invention.

The invention pertains to the pipeline monitoring technology, particularly a fiber pipeline monitoring system. The system is composed of an optical transmitter module, an optical interferometer module, a monitoring line, a modulator module, an optical receiver module and a signal processing module. The system can get two signals corresponding to different optical path positions of the same vibration though multiplexing a fiber interference system, compare the spectrum characteristics of the two signals, and eliminate the interference of the position information caused by the vibration information so as to obtain the accurate vibration position information under the condition that the system adds no photoelectric detector. The position information is obtained through the medium value of the spectrum amplitude ratio of the two signals, and the difference caused by the instability of the detection signal is eliminated, thus the accuracy of the location is greatly improved. The location function is realized with single-core fiber under the condition of not constituting a loop, thus the location monitoring can be realized by paving equal-distance main line along the petroleum pipe line, which has strong environmental applicability.

Method and apparatus for noise reduction in ultrasound detection with the steps of: an optical interferometer having a reference arm and a signal arm that includes a polarization-maintaining probing fiber having a reflective coating at a distal end, a way to couple the probing fiber to ultrasound, a way to generate two output beams from the interferometer, a device to modulate the polarization state of the light in the probing fiber, and a detection mechanism responsive to the ultrasonic signals at the distal tip of the probing fiber.

In an optical interferometer, polarization dependence attributable to the optical path difference has conventionally been eliminated by inserting a half-wave plate at the center of the interferometer. However, light induced by polarization coupling produced in directional couplers used in the optical interferometer causes interference having different interference conditions from those of the normal light. Polarization rotators that effect any one of 90° rotation and −90° rotation of all states of polarization of incoming light are inserted in the optical interferometer, and thereby the interference conditions of light induced by polarization coupling are made the same as those of the normal light. Each of the polarization rotators is implemented by using two half-wave plates and by varying an angle of combination of these half-wave plates. Alternatively, each of the polarization rotators is implemented through a combination of one half-wave plate and a waveguide having birefringence properties.

The invention discloses an optical interferometer which can be used to provide simultaneous measurements over multiple path lengths and methods to employ such an interferometer as to achieve a variety of functions covering simultaneous measurements at different depths separated by an increment of a multiple differential delay in the interferometer as well as simultaneous polarization measurements from a given depth and imaging. Configurations and methods are presented to encode the axial length in an object under investigation using frequency shifting as well as chirping the frequency of signals determining the frequency shifting. Methods are disclosed on the combination of multiple path configurations as to achieve versatile functionality in measurements, by using either broadband excitation or swept source excitation, combined with either discreet frequency shifting or chirped frequency shifting. Under swept source excitation, the invention discloses a long axial range apparatus, with constant sensitivity.

There is provided an information recording medium and a method of manufacturing a glass substrate for information recording media as well as a glass substrate manufactured using the method, according to which the take-off height (TOH) of a HDD for example can be made low. The surface shape in a predetermined region of an information recording medium is measured using an optical interferometer or an atomic force microscope. The measured surface shaped is subjected to line analysis along the circumferential direction of the information recording medium. A calculation is made of the product PSD×f of PSD corresponding to a predetermined wavelength ν and the reciprocal of the predetermined wavelength ν. The maximum value of the calculated PSD is controlled to not more than a predetermined value. As a result, the TOH can be made low by reducing waviness which hinders the magnetic head of a HDD or the like from stably flying.

The invention relates to a method and a system for improving phase stability of a photon microwave signal. The method comprises the following steps that: light output by a laser device is divided into two beams of vertical polarized light by a polarized light beam splitter; a reference light is combined with transmission light via a polarized light beam combiner after frequency-shift, and passes through the polarized light beam splitter after passing through a light micro-wave modulation and a light delay link, finally the reference light is interfered by the transmission light after being rotated and polarized by a faraday rotation mirror, and then a beat frequency signal is detected through a low-speed photodetector; the beat frequency signal is subjected to phase comparison with a 25MHz reference signal to obtain a phase disturbance situation of a transmission system, and the signal output by a phase discriminator is used as a control signal of a microwave photonic phase shifter after being processed. The system comprises a DFB (distributed feedback) laser device, the polarized light beam splitter, an acoustooptic frequency shifter, the polarized light beam combiner, an RF (radio frequency) signal generator, a Mach-Zehnder modulator, the photon microwave signal phase shifter, the polarized light beam splitter, an optical interferometer, a low-frequency optical receiver phase discriminator and a proportion integrator.

Provided is an optical phase modulating method and apparatus for a quantum key distribution. When an optical phase modulator is arranged outside an optical interferometer, a configuration of the optical interferometer may be simplified, and an extension of an optical path caused by the optical phase modulator, instability and an insertion loss increased in the optical interferometer, and the like, may be overcome. An output feature may be improved by adjusting an applied voltage of the optical phase modulator arranged outside the optical interferometer.

The invention relates to a system for measuring half-wave voltage of a phase modulator and a measurement method. The measurement system comprises a laser generator, a polarization controller, a microwave signal generator, an optical interferometer, a power meter and a processor. The method comprises the following steps of: connecting a phase modulator to be measured into a detection system; determining working parameters of the system, and adjusting working conditions of the system; measuring optical power values under the condition of modulating microwave signals with different amplitudes, and comprehensively processing data; and measuring the half-wave voltage at different frequencies. By the system and the method, all the parameters measured at the same detection frequency are comprehensively processed by the characteristic of high resolution of modulation signals generated by the microwave signal generator to obtain a half-wave voltage value at the frequency, and the half-wave voltage value is circularly processed to obtain half-wave voltage values at various detection frequencies; and therefore, the system and the method have the characteristics that the system and the method are high in resolution of measurement frequency, the phase modulator has a plurality of measurement frequency points and a plurality of half-wave voltage measurement values and is high in accuracy, the using performance of a high-speed phase modulator can be exerted, the system and the method are systematical in measurement and low in measurement cost, and the like.