38results about How to "Low modulation voltage" patented technology

The invention relates to an atomic spin procession detecting method and an atomic spin precession detecting device based on electro-optic modulation. Alkali metal atoms in a spin-exchange relaxation free state are used for sensing an external magnetic field or angular rate, thereby generating atomic spin Larmor precession. An electro-optic modulator is used for performing electro-optic modulation on detected laser. Through output light strength detection by the electro-optic modulator and demodulation of a phase-locked amplifier, output light strength and frequency doubling signal strength are obtained. Finally a signal acquisition and processing circuit measures an atomic spin precession signal, and furthermore measurement to the external magnetic field or inertia can be realized. According to the atomic spin procession detecting method and the atomic spin procession detecting device, advantages such as simple modulation, small size, high sensitivity, low temperature effect and simple operation condition in the electro-optic modulator are exerted. The atomic spin procession detecting method and the atomic spin procession detecting device have relatively high sensitivity and relatively high stability. The novel atomic spin procession detecting method is based on an atomic spin effect and can be used for industrial integration and practical application of atomic spin sensing devices in future.

The invention discloses a resonant type fiber-optic gyroscope frequency locking device.The resonant type fiber-optic gyroscope frequency locking device comprises a light source driving module, a narrow linewidth laser source, a Y waveguide modulator, a first modulation module, a polarization maintaining optical fiber resonant cavity, a signal demodulation detection module, a second modulation module, a digital output module and a lithium niobate straight waveguide modulator.A laser works at constant temperature and constant current and in a steady state, frequency stability is good, and frequency noise introduced by frequency modulation of the laser is effectively lowered.Different from a traditional PZT intra-cavity modulation method, no movable part is arranged in the cavity, the effective refractive index is modulated by modulating the magnitude and direction of an electric field applied to lithium niobate waveguides, equivalent cavity length modulation is achieved, and reliability is high.The modulation voltage is low, no redundish external driver is needed, the structure is simple, and the size and power consumption of a gyroscope are easily reduced.The lithium niobate waveguide modulator has a polarization function and achieves a polarization selection effect in the cavity, the intra-cavity polarization extinction ratio is increased, and noise relevant to polarization is effectively restrained.

The invention belongs to the field of laser devices, and particularly relates to an acousto-optic Q-switched ytterbium-doped all-fiber laser. In order to solve the problems of low coupling efficiency, high maladjustment sensitivity, complex experimental facilities and the like caused by separated component structure in Q-switched fiber laser, the invention adopts a technical proposal of the acousto-optic Q-switched ytterbium-doped all-fiber laser which comprises a fiber bragg grating (FBG), an acousto-optic modulator (AOM) with tail fiber, a multimode coupler, two pumping light-emitting diodes (LDs), ytterbium-doped double-clad fiber and output tail fiber, wherein the two pumping LDs couple pumping light to the ytterbium-doped double-clad fiber respectively by the multimode coupler; the ytterbium-doped double-clad fiber is connected between the output terminal of the multimode coupler and the output tail fiber; the FGB is connected to a signal terminal of the multimode coupler by the AOM with tail fiber, and forms a resonant cavity with the end surface of the output tail fiber simultaneously; and alternating voltage is applied on the AOM. The invention is mainly used in the manufacturing and designing of lasers.

The present invention relates to a quantum coder and decoder with phase modulated polarization state and their application method in the quantum secure communication. Four-state quantum coder or decoder is formed from a phase-polarization controller and a ture random generator, and can implement quantum secure communication using "two linear polarization states and two circular polarization states" four-state coded BB84 protocol; and six-state quantum coder or decoder is formed from two phase-polarization controllers and a synchronous trigger, and can implement six-state coded quantum secure communication.

An electro-optic modulator includes a waveguide of a nonlinear optical material and an electrode line for generating an electrical field in a modulating region of the waveguide when a voltage is applied to the electrode line, thereby modulating light passing through the waveguide. Therein, the forward electro-optic response of the modulating region is the same as the backward electro-optic response; and the electro-optic response has a band-pass or a low-pass characteristic. A distance measuring device includes a light source emitting light, and such an electro-optic modulator arranged such that the emitted light passes through the electro-optic modulator in a first direction before being emitted from the distance measuring device, and after being reflected from a target passes through the electro-optic modulator in a second direction which is opposite to the first direction.

A distance measuring device includes a light source emitting light, and an integrated electro-optic modulator arranged such that the emitted light passes through an optical waveguide of the electro-optic modulator in a first direction before being emitted from the distance measuring device, and after being reflected from a target passes through the electro-optic modulator in a second direction which is opposite to the first direction. The forward electro-optic response of a modulating region of the electro-optic modulator is the same as the backward electro-optic response, and a center of gravity of the modulation is independent of modulation frequency.

The invention relates to an acousto-optic Q-adjusting airflow chemical laser apparatus. A resonant cavity of the apparatus employs a folded stable cavity structure. A blazed grating, an acousto-optic Q switch, a film Polaroid, a gain medium, a planar mirror 1, a planar mirror 2 and a plane concave front cavity mirror are successively arranged along the forward direction of output laser. According to the invention, the laser apparatus carries out Q adjustment by use of an acousto-optic effect of an acousto-optic medium, and through applying modulation signals to driving power supply signals, realizes periodical abrupt change of a high-Q value and a low-Q value of the resonant cavity so as to realize Q-adjusting pulse output of an airflow chemical laser. The apparatus has the advantages of compact structure, low power consumption, good pulse stability and reliability, capability of realizing high-repetition-rate and high-peak-power output, and the like, thereby being widely applied to such fields as photoelectric confrontation, laser remote sensing, laser detection and the like.

The invention relates to a self-aligned graphene field emission gate structure and a preparation method thereof, and belongs to the field of vacuum electronic devices. The structure comprises a substrate; insulating layers which are deposited on the substrate, and are arranged on the substrate at intervals; a grid electrode which is deposited on the insulating layers; emission conical tips which are arranged on the substrate between the insulating layers; and graphene which is flatly laid on the grid electrode. One pole of a grid voltage power supply is applied to the substrate, and the other pole of the grid voltage power supply is applied to the grid electrode, so that grid voltages of different magnitudes are applied between the substrate and the grid electrode, and further controllable etching is carried out on the graphene to form a self-aligned grid electrode hole. A very low grid voltage is applied between the substrate and the grid electrode, so that a greatly enhanced electric field can be formed at the emission conical tip, the number of emitted electrons is changed by changing the magnitude of the grid voltage, controllable etching is performed on an upper graphene layer, a self-aligned grid electrode hole is finally formed, the modulation voltage of the grid electrode is greatly reduced, and the electron transmittance is effectively improved.

The invention discloses an optical waveguide chip based on erbium-doped lithium niobate and a mode-locked laser. The chip sequentially comprises a substrate, a silicon dioxide cladding, an erbium-doped lithium niobate film and a radio frequency electrode from bottom to top; the erbium-doped lithium niobate thin film is etched through photoetching, and a ridge-type erbium-doped lithium niobate waveguide is formed; and the radio frequency electrodes are arranged on the two sides of the erbium-doped lithium niobate waveguide in parallel. The erbium-doped lithium niobate thin film is used as the waveguide, the low-noise gain characteristic of the erbium-doped waveguide is reserved, the electro-optical characteristic of the lithium niobate waveguide is introduced, the gain and modulation requirements of the active mode-locked laser are met, and the integrated active mode-locked laser which is low in noise and continuously adjustable in repetition frequency can be achieved in cooperation with direct-current bias. The distance between electrodes is reduced through the ridge-type erbium-doped lithium niobate waveguide, the needed modulation voltage and electric power consumption are reduced, overlapping of signal light and pump light speckles can be increased through strong constraint on the signal light and the pump light speckles, and the pump efficiency is improved.

The invention discloses a dielectric adjustable film based on an implantable nano-wire electrode. Titanium silicide conductive film layer, titanium silicide conductive nano-wire layer and dielectric medium film layer are orderly deposited on a basic board from bottom to top. The film can be prepared by magnetron sputtering deposition and sol-gel method. The dielectric adjustable film based on an implantable nano-wire electrode implants silicide conductive nano-wire into the inner of the dielectric film, makes full use of the marginal electric field of the nano-wire electrode, gets a high adjustability under a very low modulating voltage and reduces the modulating voltage of the dielectric adjustable film without nano-wire electrode, which is from 1/6 to 1/10 of in the ordinary course. The dielectric adjustable film based on an implantable nano-wire electrode of the invention has good compactness, little defects and loss. The dielectric film based on an implantable nano-wire electrode is an adjustable film with high adjustability, low loss, and high performance, thereby having a nice prospect of application.

The invention discloses an optical field frequency multiplication sweep device based on an electro-optical material optical waveguide. The optical field frequency multiplication sweep device comprises a substrate, a first mask plate, a second mask plate, a waveguide core layer, a sawtooth electrode, a double-contact-pin signal electrode, a first double-contact-pin ground wire electrode, a second double-contact-pin ground wire electrode, a matched resistor, a first signal input port and a second signal input port. According to the invention, heat is generated when current passes through the double-contact-pin signal electrode, so that the thermo-optic effect of the waveguide core layer and the driving voltage and the phased array for controlling the periodic change of the refractive index in the core layer realize frequency doubling modulation of mode sweep, and the required modulation voltage and the modulation frequency of the required modulation signal are effectively reduced. The optical field frequency multiplication sweep device based on the electro-optical material optical waveguide can be widely applied to the field of optical waveguide devices.