172 results about "Kerr effect" patented technology

A transmitter for an optical transmission system transmits an optical sub carrier multiplexed signal comprising number of sub-carriers, onto an optical transmission path, and provides spectral shaping by different magnitudes of the sub-carriers, or different modulation formats for different sub carriers. This spectral shaping can reduce performance degradation by Kerr effect optical non linearities. This can mean higher input powers may be launched. The magnitudes can provide a signal spectrum which is lower near a centre of a band of sub carriers than near an edge of the band. Such spectral shaping can be provided in the receiver either to undo the pre emphasis in the transmitter, or to reduce non linearities from components at the receiving side.

The invention belongs to the optical technical field, in particular to a measuring device of magneto-optical kerr effect on longitudinal surface of a large field. The device consists of an electromagnet, a program control magnet power supply, a light path system and an operation control system (PC), wherein, the light path system subsequently consists of a semiconductor laser, a polarizing prism, a half transparent and half reflecting prism, a polarization detecting prism, a photodetector, a convex lens, a sample holder, an aperture, another polarization detecting prism, a long focal length convex lens and another photodetector; a magnetic filed for measurement is provided by the electromagnet which can provide a magnetic filed up to 1.5 tesla when the magnetic pole spacing is 4cm. The invention uses a converging convex lens to effectively expand the incident angle and the reflection angle of the light on the surface of the a sample, overcome the restriction of the magnetic pole spacing to the incident angle of the laser and enhance the magneto-optical kerr signal intensity on the longitudinal surface. The invention makes measurement of the high-coercivity magnetic film by the magneto-optical kerr effect possible.

A laser device (100), configured for generating laser pulses, has a laser resonator (10) with a gain disk medium (11) and a Kerr medium (12). The laser resonator (10) includes a first mode shaping section (13) which is adapted for shaping a circulating electric field coupled into the gain disk medium (11), and a second mode shaping section (14), which is adapted for shaping the circulating electric field coupled into the Kerr medium (12) independently of the electric field shaping in the first mode shaping section (13). Furthermore, a method of generating laser pulses (1) using a laser resonator (10) with a gain disk medium (11) and a Kerr medium (12) is described.

The invention discloses a multifunctional reflection-type magneto-optic spectrum measuring system which uses a super-continuous white light source, a grating monochromator, a plurality of polarized lenses, a photoelastic modulator, a broad band 1/4 and 1/2 wave plate, a non-polarization beam splitter (NPBS), a single-ended differential detector and an OXFORD low-temperature superconducting magnet system to form a spectrum detection system with a flexible and variable structure. The invention can realize the measurement of reflection-type magnetic circular dichroism (MCD), polar magneto-optical Kerr effect, polarized reflection spectrum and magnetic wire magnetic linear dichroism (MLD) on the same light path. The system has high sensitivity and can be used for fields, such as basic physics research, material characteristic analysis, light polarization modulation communication and the like.

The invention discloses a system for measuring linear and non-linear magneto-optical Kerr rotation, which comprises an ultra-short pulse laser, a helium-based closed-cycle refrigerator, an electromagnet, a laser-pumping optical path, a laser-detection optical path, a linear Kerr signal collection optical path, a non-linear Kerr signal collection optical path, a lock-in amplifier signal collection system and a laser spot monitoring system, wherein the helium-based closed-cycle refrigerator is provided with optical windows and used for controlling the temperature of a sample; the size of the air gap and the magnitude of the magnetic field of the electromagnet are adjustable; the laser-pumping optical path is used for leading in the laser inputted by the ultra-short pulse laser and focusing the laser on the surface of the sample inside the refrigerating head, so as to excite the sample; the polarization plane of the laser-detection optical path rotates after a beam of laser outputted by the ultra-short pulse laser is reflected by the sample; the linear Kerr signal collection optical path is used for collecting the base-frequency signal of the detection laser; the non-linear Kerr signal collection optical path is used for receiving the frequency-doubled signal of the detection laser; the lock-in amplifier signal collection system is used for filtering and amplifying the signals and transmitting the signals to a computer for processing; and the laser spot monitoring system is used for accurately controlling the overlap ratio of the pumped beam laser spot and the detected beam laser sport. The system provided by the invention for measuring the linear and non-linear magneto-optical Kerr rotation is capable of simultaneously adjusting the temperature and the intensity of the magnetic field applied to the sample and achieving the measurement of the linear and non-linear magneto-optical Kerr effect on a temperature-variable steady-state basis or a time-resolved dynamic basis.

The invention discloses an anti-counterfeiting component and an anti-counterfeiting product, wherein the anti-counterfeiting component comprises a base layer. A magneto-optical information layer is arranged on the base layer, machine-readable safety information based on a magneto-optical characteristic is loaded on the magneto-optical information layer. The magneto-optical characteristic comprises a magneto-optical faraday effect or a magneto-optical Kerr effect. The anti-counterfeiting product comprises an object which is provided with the anti-counterfeiting component. The anti-counterfeiting component is adhered to the object through a first adhesive layer and/or a second adhesive layer. An embodiment of the anti-counterfeiting component and the anti-counterfeiting product can improve anti-counterfeiting performance of the anti-counterfeiting component and safety of the anti-counterfeiting product.

The invention relates to a setting method of a self-locking model laser. Pump light irradiates into a laser cavity resonator from an end surface of a laser crystal; a beam shaping system is adopted to enable the light intensity at the central part of a pump luminous spot to be less than the surrounding light intensity so as to cause a Gauss beam with a sunken part in the center; the laser crystalis used as a model locking part while used as a laser gain crystal; an area similar to a diaphragm is formed at the center of the laser crystal; the size of the diaphragm area can be controlled through adjusting a pump beam; the Kerr effect of the crystal and a soft diaphragm commonly act to complete the starting and maintenance for laser running of the locking model and realize the ultrashort pulse output of a continuous locking model or realize the locking model pulse output of Q regulation. The invention solves the problem existing in the existing ultrashort pulse laser that the system is huge, peripheral equipment is more, the precision required by the modulation is high, and self-starting can not be performed, improves the efficiency, reduces the cost and has very high application value.

An optical fiber for communications systems, the fiber being designed to ensure a compensation of Kerr effects. The fiber has a profile which ensures that changes in power produce changes in distribution of power between core and cladding, such that the phase change associated with the changed spatial distribution of the power, is equal and opposite to the phase change due to Kerr Effect.

A liquid crystal display includes a liquid crystal layer causing a selective reflection and exhibiting Kerr effect, first and second electrodes applying voltage to the liquid crystal layer, a first circular polarizer disposed between the liquid crystal layer and a viewer and allowing a first circularly polarized light incident on the liquid crystal layer when irradiated with a natural light, the first circularly polarized light having an electric-field vector rotating in a direction reverse to a rotation direction of an electric-field vector of a circularly polarized light selectively reflected by the liquid crystal layer, and a second circular polarizer facing the first circular polarizer with the liquid crystal layer interposed therebetween and allowing a second circularly polarized light incident on the liquid crystal layer when irradiated with a natural light.

The invention discloses a spectrum magneto-optical ellipsometry analysis device of a rotary compensator as well as application thereof. The spectrum magneto-optical ellipsometry analysis device comprises a light source module, a light path module, a magnetic field module, a sample table, a motor control module and a detection and analysis module, the light path module comprises a collimating lens,a polarizer, a compensator and a polarization analyzer, the detection and analysis module comprises a computer and a detector, the collimating lens, the polarizer, the compensator, the sample table,the polarization analyzer and the detector are sequentially arranged along a light path direction, the polarizer and the compensator are located in an incidence light path, the polarization analyzer is located in an emergence light path, and the incidence light path and the emergence light path are located at the two sides of the sample table and respectively keep an included angle Phi with normalof the sample table. The device disclosed by the invention can represent optical and magnetic parameters of a magnetic film material under longitudinal or poloidal magneto-optical Kerr effect, can obtain thickness, optical parameters and magnetic parameters of a magnetic film sample during one test and is relatively high in automation degree.

A dielectric liquid layer is sandwiched between a pixel substrate and a counter substrate, at least one of which is a transparent. The dielectric liquid layer is made from a liquid that is macroscopically isotropic and transparent, but has clusters microscopically, the clusters being agglomerations in each of which liquid crystal molecules are aligned in short distance order. Because of the presence of the cluster even at a temperature equal to or higher than the liquid crystal-isotropic phase transition temperature of a liquid crystal compound, reduction of the Kerr effect is suppressed even if the temperature rises. For example, clusters containing, for example, (a) a liquid crystal compound having an ability of forming an intermolecular hydrogen bond, (b) a liquid crystal compound having a smectic phase, (c) a particulate, (d) or the like, has a large cluster size and thus have a long life even if the temperature rises.

A nonlinearity compensation technique for a CO-OFDM transmission system in which a proportion (e.g. up to 50%) of OFDM subcarriers is transmitted along with a phase-conjugate copy (PCP) on another subcarrier (replacing a data carrying subcarrier) to enable nonlinear distortion compensation. Nonlinear distortion experienced by closely spaced subcarriers in an OFDM system is highly correlated. The PCPs are used at the receiver to estimate the nonlinear distortion (e.g. nonlinear phase shift) of their respective original subcarriers and other subcarriers close to the PCP. With this technique, the optical fibre nonlinearity due to the Kerr effect in OFDM systems can be effectively compensated without the complexity of DBP or 50% loss in capacity of the phase conjugate twin wave (PC-TW) technique. Moreover, the technique proposed herein can be effectively implemented in both single polarization and PMD systems, in both single channel and WDM systems.

The invention discloses a magnetic imaging device and imaging method based on a diamond NV color center and a Kerr effect. A spinning control light source module provides a beam of incident laser, theincident laser passes through a dichroscope system and irradiates the NV color center of the diamond probe after being focused by the microscope objective lens, and fluorescence generated by the NV color center returns to the dichroscope system through the microscope objective lens and enters the fluorescence detection module. The polarized light generation module generates polarized light, the polarized light enters the microscope objective lens through transmission and/or reflection of the dichroscope system and then irradiates a sample placed on the displacement table, and after the polarized light is reflected by the sample, part of the polarized light enters the microscope objective lens again and then enters the polarized light detection and imaging module through the dichroscope system. Through the compatible design, high-resolution, global and large-view imaging of the sample is realized.

A Raman distributed feedback (DFB) fiber laser is disclosed. It includes a pump source and a Raman gain fiber of a length smaller than 20 cm containing a distributed feedback (DFB) grating with a discrete phase structure located within no more than 10 % off the center of the grating and wherein the Raman DFB fiber laser generates a laser signal with an optical spectrum, which has an optical bandwidth at half maximum optical intensity of less than 1 gigahertz (GHz) (wherein a maximum intensity frequency is different from the frequency of the pump laser). The Raman laser includes compensation for the nonlinear phase change due to Kerr effect and thermal effect resulting from absorption of the optical field, thus enhancing the conversion efficiency.

The invention provides a once signal to noise ratio measuring method and a device based on a chirp pulse feature. The once signal to noise ratio measuring method and the device based on the chirp pulse feature can measure a signal to noise ratio of a once pulse. The principles include that a pumping probe light path is built by optical Kerr effect. The measuring device broadens probe light as chirp laser pulse in time and space by a grating or a prism. The probe light transmits from an analyzer due to the optical Kerr effect, a transmitted signal is collected by a scientific-level charge-coupled device (CCD), and signal to noise ratio of the laser pulse to be detected is obtained. The method introduces large negative dispersion amount by the grating or the prism, broadens probe light pulse to hundreds of picoseconds or more, and enables time window to reach hundreds of picoseconds or more. Meanwhile, a spatial light modulator is inserted in the probe light path so as to finally increase dynamic scopes.

All optical regeneration methods and systems can be realized through an exponential amplifier and a limiting amplifier, which could be two independent devices (one piece of fiber with parametric amplification and a semiconductor optical amplifier operating at saturation state) or one single device (one piece of fiber). The signal quality and the extinction ratio after regeneration are significantly improved compared with the degraded incoming data using a parametric amplifier with the data signal to be regenerated as the pump. The regenerated data has an extinction ratio as high as 14 dB, an extinction ratio enhancement of approximately 5 dB and an approximately 5 dB negative power penalty. This regeneration schemes are format transparent (RZ and NRZ), and provide noise reduction both for bit 1's and bit 0's of the data sequence. The regeneration method and apparatus that just utilizes fibers has the additional capability of ultrafast response speed (several femtoseconds due to the Kerr effect).

The invention belongs to the spatial electric field measurement field and provides a quadratic electro-optic Kerr effect-based spatial strong electric field measurement system. The objective of the invention is to eliminate the defects complexity, large size and low measurement accuracy of a traditional spatial electric field measurement technology. The system has high precision and high response speed under spatial strong electric field measurement, and can realize multipoint simultaneous measurement and nondestructive measurement. The system includes a laser generator used for generating laser, an optical path beam splitting unit used for splitting laser outputted by the laser generator into at least two beams, Kerr sensors which receive laser split by the optical path beam splitting unit and make the laser beams pass through Kerr cell units and outputted, photoelectric detectors which detect optical signals outputted by the Kerr sensors and convert the optical signals into electrical signals, and an information acquisition and processing unit which calculates a spatial electric field according to the electrical signals outputted by the photoelectric detectors.

A method and apparatus for determining volume and anisotropy field distribution of thin film granular material includes the use of a magneto-optic probe, a lock-in amplifier, and a computer. The magneto-optic probe utilizes the Kerr effect in order to determine the transverse AC susceptibility of the sample. The Lock-in amplifier determines the complex parameters of the susceptibility as a function of the DC field and AC frequency. Separate distribution values of anisotropy field and grain volume can then be determined mathematically from the relationship of complex susceptibility parameters to the DC field strength.

The invention discloses a quick measuring device and a quick measuring method for space electric fields of a liquid dielectric medium, and belongs to the technical field of high voltage and insulation measurement. The method is a quick measuring technology for space transient electric fields of a liquid dielectric medium based on an electro-optic Kerr effect and a Mach-Zehnder interferometer. The quick measuring device consists of a He-Ne laser device, a beam expander, a polarizer, a quarter-wave plate, a Kerr box, a transient voltage generator, a polarization splitting prism, a depolarization splitting prism, a total reflective mirror, a half-wave plate, a CCD (charge coupled device) image sensor. The quick measuring method comprises the following steps: firstly, regulating a light path, and directly measuring interference fringes through the CCD image sensor, visually reflecting externally applied electric fields without being limited by back-end detecting equipment, thereby realizing quick measurement for transient electric fields and making up defects of an Kerr effect alternating-current modulating method in the transient electric field measuring filed.

The invention discloses a method for realizing an all-optical diode. In a two-dimensional photonic crystal waveguide, a micro-cavity is designed on the side; and a dielectric column primitive cell is additionally arranged as a reflective layer in the photonic crystal waveguide near the micro-cavity, and the position of the reflective layer is a lattice constant deviated from the position where the waveguide is over against the micro-cavity. When the incident light intensity increases all along, the forward incident light first reaches a power threshold for exciting the nonlinear Kerr effect of the micro-cavity material, and the backward incident light is in a cut-off state under the light intensity, so as to realize the forward conduction/backward cut-off function of the all-optical diode. The working band of the all-optical diode can be adjusted by adjusting the lattice constant, and the all-optical diode is easy to be integrated in an all-optical network, so that the all-optical diode has a great application value. The all-optical diode has a response time on the order of picosecond, and the photonic crystal has the characteristic of adjusting the forbidden band range according to the lattice constant of the photonic crystal.

An online detection method for magnetoelasticity performance of thin-ferromagnetic-film, which belongs to the field of engineering materials, structure deformation, and mechanical test. The device implementing the method of the invention comprises a thin-ferromagnetic-film non-uniform stress measuring light path and a film hysteresis loop measuring light path, wherein, the film non-uniform stress measuring light path comprises a laser, a beam expander, a grating, a lens, a filter screen, and a CCD camera; and the film hysteresis loop measuring light path comprises a laser, a beam expander, a polarizer, an analyzer, and a photodetector. The method of the invention comprises the steps of measuring non-uniform curvature of the thin-ferromagnetic-film surface by shearing interferometer to obtain the non-uniform stress in film, and measuring the hysteresis loop of the film by using magnetooptic Kerr effect of the thin-ferromagnetic-film surface. The method can simultaneously online measure the non-uniform stress and the hysteresis loop of thin-ferromagnetic-film, so as to provide experimental basis for the research on magnetoelasticity coupling behavior of the thin-ferromagnetic-film.

An apparatus and method of testing a magnetic medium at temperatures of interest is disclosed. Properties of the magnetic medium are determined by focusing light from a source of polarized light on a magnetic surface of the magnetic medium; measuring polarization of resulting reflected light due to the magneto-optical Kerr effect, using, for example a measuring subsystem; and varying the light source to heat the magnetic material where incident to pre-defined temperatures, thereby allowing determination of the magnetic properties using the magneto-optical Kerr effect at said pre-defined temperatures.