41results about How to "Achieve phase lock" patented technology

The invention provides a device for detecting a zero crossing point of inductive current, aiming at the technical problem that the direction of inductive current can not be accurately judged by independently adopting a digital signal processor (DSP) hardware capture module (CAP) and a hysteresis comparison method. The device comprises a current sensor, a partial pressure conditioning module, a voltage following module, a pull-up bias module, a DSP module, an input module and a liquid crystal display (LCD) module. According to the invention, the phase locking function of a single-phase phase-locked loop based on a second-order generalized integrator (SOGI) is adopted, so that the phase locking for the inductive current can be realized, and the zero crossing point and the direction of the inductive current can be further detected. Through the device, the defects that separately using a hardware or software method is adopted are overcome; and equipment is simple, detection is convenient and fast and reliability is high.

A strong coupling multi-core optical fiber includes a core area, an internal cladding area and an external cladding area. The optical fiber is characterized in that the core area includes a plurality of large cores and a plurality of sub-wavelength cores arranged in the internal cladding area; the refractive index of the internal cladding area is smaller than that of the large core and the sub-wavelength core but larger than that of the external cladding area; the internal and external cladding areas are both made of solid material with evenly distributed refractive index; the diameter of the large core is in micron dimension, the distance between adjacent large cores is in micron dimension and the diameter of the sub-wavelength core is in hundred micron dimension. The invention has the functions of strong coupling, phase locking, laser shaping and homogenization.

The invention relates to a tool-crashing prevention system of a numerically controlled lathe. The tool-crashing prevention system comprises a tool rest and the lathe on which a workpiece is clamped well. A specular reflection photoelectric switch is arranged in the middle of the tool rest. A roughing tool used for cutting the workpiece is clamped on the tool rest. The cut workpiece is fixed to the lathe through a chuck. The lathe is provided with two reflecting plates in the X-axis direction and the Y-axis direction respectively. The tool rest is moved through a stepped motor. The specular reflection photoelectric switch on the tool rest detects the position of the tool rest through optical signals reflected by the reflecting plates on the X-axis of the lathe and the Y-axis of the lathe. The moving speed and the moving direction of the tool are further judged in the mode that a control system reads the high level or the low level of a pulse signal machine of the numerically controlled lathe, so that whether a tool-crashing accident happens to the tool is judged, and emergency braking is conducted before tool crashing. The tool-crashing prevention system can effectively protect the roughing tool against the tool-crashing accident and has the characteristics of being high in accuracy, reliable in detection, low in cost and the like.

The invention relates to an external cavity coherent vertical cavity surface emitting semiconductor laser, belongs to the technical field of lasers and solves the technical problem that a coherent laser is complex in structure and poor in reliability in the prior art. The laser comprises a P-type DBR (Distributed Bragg Reflector), an active region, an N-type DBR, a substrate and an N-face electrode which are sequentially and densely arranged from top to bottom. The edge of the upper surface of the P-type DBR is provided with a P-face electrode. The P-type DBR is provided with an oxidation confinement layer with a plurality of oxidation holes. The laser further comprises a high-contrast grating composed of a grating body and an external cavity. The high-contrast grating blocks all light emitting holes and light emitting hole joints. The lower surface of the external cavity is fixed to the upper surface of the P-type DBR, the optical thickness of the external cavity is in integral multiple of half of the wavelength, and the external cavity is made from a dielectric material of low refractive index. The grating body is arranged on the upper surface of the external cavity, the polarization direction is parallel or perpendicular to the (110) crystallographic orientation, the grating body is made from a dielectric material of high refractive index. The external cavity coherent vertical cavity surface emitting semiconductor laser can achieve polarization control and is high in stability and good in reliability.

The invention discloses an optical phase locking method based on microwave photon frequency division. The method comprises the steps of: inputting coupling signals of optical signals output by two monochromatic light sources to be subjected to phase lock into a photoelectric oscillation loop, wherein the oscillation mode of microwave signals with the frequency as shown in the description in the photoelectric oscillation loop is bandpass, and [omega]0 is the difference of the output frequencies of the two monochromatic light sources; forming positive feedback oscillation by the oscillation modeof microwave signals with the frequency as shown in the description in the photoelectric oscillation loop so as to obtain stable micro signals with the frequency as shown in the description; performing phase demodulation for the micro signals with the frequency as shown in the description output by the photoelectric oscillation loop and the local oscillator micro signals, and employing a phase demodulation result after elimination of high-frequency components to perform feedback control for the phase of the at least one monochromatic light source so as to achieve the phase locking of the twomonochromatic light sources. The present invention further discloses an optical phase locking device based on microwave photon frequency division which can overcome the problem of the locking phase jitter and reduce the requirement on phase demodulation so as to achieve high-frequency and stable micro wave signal output.

The invention provides a phase-locked loop system, wherein the phase-locked loop system at least comprises the components of a delay unit which is used for delaying a reference clock signal and a feedback clock signal; and a phase-locked loop component which is connected with the delay unit and is used for outputting a first signal that is locked on the frequency and the phase of the reference clock signal based on the delayed reference clock signal and the feedback clock signal. According to the phase-locked loop system, through overlapping the delay unit into the phase-locked loop component, delaying the reference clock signal and the feedback clock signal, and performing reversal digital compensation on a phase difference between the reference clock signal and the feedback clock signal, inclination of the reference clock signal and the feedback clock signal is eliminated, and the performance of the phase-locked loop component does not reduce. Through adjusting the delay precision of the reference clock signal and the feedback clock signal, fine adjustment for the phase difference under locking of the original locked-phase loop is realized, so that under a precondition that the performance of the phase-locked loop component is ensured, 10ps-20ps magnitude phase locking can be realized.

The invention, which belongs to the technical field of photoelectric detectors, particularly relates to a balanced zero-beat photoelectric detector for non-classical light field detection in a continuous variable quantum optical experiment, in particular to a photoelectric detector for locking a relative phase between a non-classical light field and a local light field and detecting a corresponding phase non-classical light field orthogonal component in a broadband range. The invention aims at providing balanced zero-beat detector having advantages of low noise, high gain and wide bandwidth, thereby solving a problem of detection of specific orthogonal components of a broadband compressed light field and thereby realizing measurement of a specific orthogonal component of compressed light in a broadband range under phase locking of the compressed light and local light. The balanced zero-beat photoelectric detector has advantages of low noise, high gain, wide broadband, alternating-current and direct-current monitoring and phase locking and the like. The balanced zero-beat photoelectric detector can be well used for detecting the orthogonal component of the compressed light after therelative phase between the compressed light and the local light is locked.

The invention discloses a surface-emitting semiconductor laser chip and a preparation method thereof. The semiconductor laser chip is a surface-emitting two-dimensional array light source chip emitting laser from a substrate layer; and the distance between the centers of two adjacent light sources is equal. The chip is sequentially provided with a substrate layer, a front mirror, an active layer,an oxidation optical limiting layer, a rear mirror and an ohmic contact layer from bottom to top; the thickness of the substrate layer, the distance between the surface emitting array light sources and laser wavelength meet a Talpot relational expression; a first electrode is manufactured at the top of the ohmic contact layer; a passivation layer is manufactured at a certain position of the firstelectrode, wherein the position of the first electrode does not contact with the ohmic contact layer; a groove structure is manufactured at the position, corresponding to the oxidation aperture of theoxidation optical limiting layer, of the light-emitting side of the substrate layer, a second electrode is manufactured at the groove position of the substrate layer, and the second electrode and thefirst electrode at the top of the ohmic contact layer are opposite in electrical property; and the non-electrode position of the light-emitting surface of the substrate layer is plated with a semi-reflecting and semi-transmitting film, and laser is emitted at the position.

The invention discloses a high-power external cavity semiconductor laser device. An outer cavity VCSEL array surface light source is composed of a plurality of VCSEL array light sources, wherein a P-type epitaxial layer of each VCSEL array light source is a multi-film total reflection P-type epitaxial layer, an N-type epitaxial layer of each VCSEL array light source is a multi-film partial reflection N-type epitaxial layer, reflectivity of each N-type epitaxial layer is 50-90%, the outer cavity VCSEL array surface light source is installed on a concave surface of a concave surface reflector, agroove is formed in the middle of a 45-degree oblique angle cylindrical reflector, and a convex surface outer cavity reflector is installed in the groove and right faces the outer cavity VCSEL arraysurface light source. The laser device is advantaged in that a coupling resonant cavity is formed by a concave reflector, the multi-film total reflection P-type epitaxial layer, the multi-film partialreflection N-type epitaxial layer and the convex outer cavity reflector, loss of different transmission modes is controlled by utilizing the feedback adjustment effect of the coupling resonant cavityof the light beam, a high-order mode is suppressed, so phase locking between array units is realized, and the light beam quality of an output light beam is improved.

The invention provides a semiconductor laser coherent array, and the array is characterized in that the semiconductor laser coherent array comprises a multi-mode interference region which comprises amulti-stage one-to-two multi-mode interference coupling structure and a plurality of bent waveguides, wherein the multi-mode interference coupling structure between different stages is connected through the bent waveguides, and the multi-stage one-to-two multimode interference coupling structure is used for generating a plurality of phase coherent optical branches; a reflection region which is used for transmitting the plurality of optical branches and controlling the energy ratio output by the optical branches by adjusting the reflectivity; and an array region which comprises a plurality of channel waveguides and is used for carrying out power amplification on the plurality of optical branches output by the reflection region and then outputting the amplified optical branches. The invention further provides a preparation method of the semiconductor laser coherent array.

The invention discloses a phase-locked amplification method and system in TDLAS gas detection. The method comprises the following steps of acquiring the amplitude and frequency of a modulation current corresponding to a gas to be detected; obtaining a phase angle of a frequency multiplication component in a gas absorption spectrum signal It, wherein the phase angle eta of the frequency multiplication component is a signal deviation phase angle; setting a parameter and taking the parameter as a phase of a k frequency multiplication reference signal; repeatedly adjusting until the k-order harmonic wave is close to an ideal harmonic wave waveform; and obtaining a value when the k-order harmonic wave is close to the ideal harmonic wave waveform, and assigning the value to the phase angle of a double component and the obtained eta to realize phase locking. According to the invention, the problem caused by phase-locked amplification in the gas detection by using a hardware phase-locked loop in the prior art is solved, so that the hardware cost is reduced, and the gas detection precision is improved to a certain extent.

The invention provides an optical comb control method and system based on an electric control polarization controller. The system comprises a laser light source used for providing seed light, an amplifying device used for amplifying the energy of the seed light, a self-reference beat frequency detection device used for detecting and obtaining a repetition frequency signal and a carrier envelope phase signal, and a phase locking device used for locking the repetition frequency signal and the carrier envelope phase signal. The polarization state of the seed light in the optical fiber is controlled by applying a driving voltage through the electric control polarizer and the module, and nonlinear polarization rotation of the seed light is realized; locking of the carrier envelope phase signalis realized by controlling the polarization state of the seed light in the resonant cavity; phase locking of repetition frequency signals is achieved by controlling the length of the resonant cavity.

The invention relates to the technical field of rotating part surface deformation and pressure distribution measurement, in particular to a rotating part surface deformation and pressure distribution synchronous measurement system. The system comprises a laser light source module, an image acquisition module, a synchronous control module and a rotating part carrier, the laser light source module is a laser light source capable of outputting 10ns pulse width; the image acquisition module comprises two cross-frame CCD (Charge Coupled Device) cameras, and the two cross-frame CCD cameras are used for acquiring two images within a set time interval; the synchronous control module is used for providing a trigger signal of the laser light source module and an acquisition signal of the image acquisition module; the rotating part carrier comprises a rotating part to be measured, and the surface of the rotating part to be measured is provided with PSP coating and speckle mark points. The system effectively controls motion blur of the rotating part, so that an image is clear and visible; and phase locking of the high-speed rotating component is realized.