866 results about "Light extinction" patented technology

The invention discloses a laser driver and a temperature compensation circuit thereof. The temperature compensation circuit comprises a benchmark voltage generation unit, a benchmark current generation unit, a reference voltage generation unit, and a compensation current generation unit, wherein the benchmark voltage generation unit generates a benchmark voltage which increases with the increase of the temperature; the benchmark current generation unit is connected with the benchmark voltage generation unit and outputs benchmark current which increases with the increase of the benchmark voltage; the reference voltage generation unit generates a reference voltage which increases with the increase of the temperature; the compensation current generation unit is connected with the reference voltage generation unit, obtains the compensation threshold temperature according to the reference voltage, and outputs compensation current when the temperature is higher than or equal to the compensation threshold temperature; and the benchmark current and the compensation current are overlapped to form benchmark modulation current. The laser driver comprises the temperature compensation circuit and a bias current regulation circuit. An optical signal output by the laser can have constant extinction ratio by compensating modulation current of a laser through the temperature compensation circuit, and the laser can obtain steady output optical power by compensating bias current of the laser through the bias current regulation circuit.

A method of measuring fluid flow including the steps of providing a light source including at least one LED, providing an image detecting element and defining an illuminated measurement space with an optical element located between the measurement space and the image detecting element. The measurement space is located optically in-line between the light source and the image detecting element. The method further includes the steps of providing a fluid flow through the measurement space, the fluid flow including particles, and illuminating the measurement space with the light source to induce light extinction from the particles comprising shadow markers of the position of the particles within the fluid flow. The image detecting element is used to detect the shadow markers produced by the particles to record displacement of the particles as a function of time corresponding to movement of the fluid flow. In a further aspect, the light source includes plural LEDs emitting different colors.

Disclosed herein are methods, apparatus, and systems to achieve substantially constant optical power and/or extinction ratio for a semiconductor laser. In one aspect, a microcontroller of an optical transmitter may adjust an electrical current that is provided to a semiconductor laser based at least in part on a comparison of a first measured optical power of light emitted by the semiconductor laser and a predetermined target optical power. The microcontroller may then determine an electrical current that is capable of giving the semiconductor laser a substantially constant extinction ratio by evaluating an equation with the first measured optical power and a second optical power measured after the controller adjusts the electrical current.

An automatic closed loop power control system is described for simultaneously adjusting an output power and an extinction ratio P₁/P₀ of a laser diode in order to maintain a desired average output power and a desired extinction ratio. The bias current component of a laser diode drive current is adjusted to compensate for changes in the average output power caused by ambient characteristics such as temperature and aging. Simultaneously, a modulation current component of the laser diode drive current is adjusted to maintain an extinction ratio of the laser diode output signal. The bias current and modulation current adjustments are based on the second order statistics of an average output power of the laser diode and a variance in the power output of the laser diode.

A system and method are disclosed which enable deposition parameters to be controlled in producing a metal surface to tune the localized surface plasmon resonance (LSPR) wavelength of such metal surface to a desired wavelength. For example, the surface produced may be used as an enhancement surface within a surface-enhanced spectroscopy process, wherein such surface is produced having a LSPR wavelength that provides the maximum extinction of a particular excitation light. In one embodiment, a metal is deposited onto a substrate, while controlling one or more deposition parameters to tailor the LSPR of the resulting metal surface to a desired wavelength. In one embodiment, the substrate is smooth, and does not require a mask prearranged thereon for controlling the LSPR wavelength. Rather, deposition parameters, such as temperature of the substrate, deposition rate, and film thickness may be controlled to effectively tune the LSPR wavelength of the metal surface.

The invention relates to a method for preparing polyester fibers with pearly luster. The method comprises the following steps: (1) pearlescent pigment agglomerate and full-dull PET fiber forming resin slice are blended according to the weight ratio of 5-20 to 80-95; and after drying, the water content is less than 100PPM, and the slice is delivered to a feeding port of an extruder and enters an screw extruder for heat fusing and compression; (2) the temperature is controlled to between 290 and 305 DEG C, fusant extruded out by the rotary screw rod enters a metering pump through a distributing pipe and a static mixer, delivered to a spinning component, filtered by a sea sand layer and pressed into a spinning plate to form fusant current which is cooed to form in a spinning cabinet, and the surface of a filament bundle is covered by a spinning finish; and 3. the spinning speed pre-extension is between 2, 500 and 3, 500m/min, the winding carry rate is between 5 and 15 percent for wind-forming, and the full-dull pearlescent polyester fiber POY is obtained. The manufacturing process is easily realized, and is convenient to improve the pearlescent fiber spinning effect and simultaneously provides the fibers with light extinction performance, and the pearlescent pigment has excellent performance and little feed rate.

The invention discloses a device and a method for performing offset point automatic locking on an electrooptical modulator with ultrahigh extinction ratio. The offset point automatic locking device of the electrooptical modulator with ultrahigh extinction ratio comprises a laser, an electrooptical modulator, an optical switch, an electrooptical modulator offset voltage control system and a clock synchronization module, wherein the electrooptical modulator offset voltage control system comprises an electrooptical conversion signal amplification module, an analog-digital conversion module, a controller and an output driving circuit; and the clock synchronization module is used for opening an synchronization optical switch, inputting modulated electrical impulse of the electrooptical modulator radio-frequency end, and the disturbance leading-in time of the direct-current offset end of the electrooptical modulator. The method is characterized in that ultrahigh extinction ratio pulsed light output is realized through the cascade connection of the electrooptical modulator and the optical switch, and through controlling the offset voltage of the electrooptical modulator, the electrooptical modulator operates at an appropriate working spot stably. According to the invention, the offset voltage of the electrooptical modulator is controlled automatically; the pulsed light extinction ratio output by the device is improved greatly; and the energy is higher and much stable.

A polarized white light emitting diode provides a polarized white light to decrease glare, and increase the extinction ratio. A LED chip is disposed in a cavity between a reflection substrate and a metallic wire-grid polarizing layer, and emits a first color light. The metallic wire-grid polarizing layer is disposed under and in contact with a transparent substrate. A phosphor layer covers over the LED chip, and is disposed in the cavity with an air gap between the phosphor layer and the metallic wire-grid polarizing layer. A second color light is generated by the first color light. The metallic wire-grid polarizing layer multiply reflects a portion of first color light in plural directions in the cavity to produce secondary excitations. The polarized white light transmits through the metallic wire-grid polarizing layer by mixing a portion of first color light with the second color light excited by the first color light.

The invention discloses a two-dimensional stratified material based SOI (Semicon-on-insulator) base micro loop filter. The two-dimensional stratified material based SOI base micro loop filter comprises an SOI substrate which is formed by a buried oxide layer and top silicon; an SOI micro loop resonant cavity, input straight waveguide and output straight waveguide are arranged on the top silicon and the input straight waveguide and output straight waveguide are arranged on the upper side and the lower side of the SOI micro loop resonant cavity, so that the SOI waveguide structure is formed; two-dimensional stratified materials cover the SOI waveguide structure; two ends of the input straight waveguide are provided with input end optical grating and direct connection optical grating; one end of the output straight waveguide is provided with output end optical grating; areas of the SOI micro loop resonant cavity, which are close to the input straight waveguide and the output straight waveguide, form into a first coupling area and a second coupling area. Compared with the traditional technology, the two-dimensional stratified material based SOI base micro loop filter has the advantages of being narrow in 3dB band width, high in extinction ratio, less in noise, compatible with CMOS technology and widely applied to the on-chip optical interconnection network in the future due to the fact that the SOI base filter is further filtered due to the saturated absorption effect of two-dimensional stratified materials.

The present invention discloses a method for debugging the average optical power and extinction ratio parameter of optical transmitter. The optical transmitter is set to an automatic power control mode. The modulation signal coupling mode of the laser driving chip of light transmitter and the laser is set to a direct-current coupling mode. A microcomputer tests the luminous efficiency and threshold current of laser of the optical transmitter. The microcomputer debugs the average optical power of optical transmitter to a preset average optical power area. The microcomputer debugs the present extinction ratio of optical transmitter to a preset extinction range. The technical scheme according to the invention can greatly reduce the investment of product line on the device and has the advantages of automatic debugging realization, reduced production cost and increased production efficiency.

The present invention provides a metal wire grating polarizer and a preparation method thereof, which belongs to optical devices. The object is that the present invention is of high polarized light extinction ratio, high luminous flux, simple structure and the wide range of working wavelength. The polarizer of the present invention deposits a metal aluminum nanometer wire gating on a substrate. The substrate is optical materials which are transparent from ultraviolet band to infrared band. The structure parameter of the metal aluminum nanometer wire gating is as follows: the wire gating cycle length ranges from 40 to 80 nanometers; the wire gating duty cycle is 40 percent to 60 percent; the interlayer distance is 10 to 20 nanometers. The method steps of the present invention are as follows: the substrate is cleaned; a protection film is deposited on the surface of the substrate; a photoresist is spin coated; the nanometer wire gating structure is formed on the surface of the photoresist; the nanometer wire gating structure is carved on the protection film; nanometer wire gating structure is carved on the substrate; the rest protection film is eliminated; an aluminum metal film is coated on the vertical surface of the substrate; a parallel strip nanometer wire gating is formed. The polarization extinction ratio of the wideband polarizer of the present invention can reach 33 to 37dB in the wave band range of 300 to 5000 nanometers, and the polarized light transmittance can reach 68 percent to 94 percent.

The invention provides a polarized light irradiation device for light aligning, capable of getting polarized light with excellent extinction ratio in a wavelength region less than 300nm, furthermore, in the region, transmittance will not be changed and the polarization axis will not rotates even if the incident light to the polarization element has different angles. Workpieces (4) is conveyed facing to the direction of an arrow in the view, the light from a light irradiation part (6) is polarized by a wire grid type polarization element (1) and irradiates onto the workpieces (4) which is conveyed below the light irradiation part (6) for light aligning process. The grid of the wire grid type polarization element (1) is made from titanium oxide TiOx, can obtain polarized light with a extinction ratio above 15:1 in a range of wavelength from 240nm to 300nm, and in the region with wavelength under 300nm, the transmittance will not be changed even if the incident light to the polarization element has different angles, and the polarization axis will not rotate even if the incident light to the wire grid type polarization element has different angles.

The invention discloses a monolithic integrated InGaAs line array or stacked array detector for a sub-wavelength micro-polarization grating. The detector is a photoelectric detector and consists of an InGaAs photosensitive chip, an anti-reflection film and the sub-wavelength micro-polarization grating, wherein the anti-reflection film is made of a low-refractive index SiO2 material, and the extinction ratio of the sub-wavelength micro-polarization grating is improved; the sub-wavelength micro-polarization grating is a polarization grating line array or array consisting of polarization units in different polarization orientations; and each polarization unit is a metal polarization grating of which the grating period is shorter than that of an incident light wavelength. The sub-wavelength micro-polarization grating is integrated on a chip of a near-infrared detector, and the invention has the main advantages that: (1) the polarization grating is monolithically integrated with the detector, an optical system is simplified, and motion parts of a polarization scanning system are eliminated; (2) high-accuracy angle quantification can be achieved, and an angle error is avoided; and (3) the polarization units in the different polarization orientations are imaged simultaneously, and accurate polarization information is acquired from a moving target.

The invention relates to a preparation method of waterborne polyurethane elastic dispersion. The method comprises the following steps: (1) synthesizing a siloxane polymer: polymerizing a compound as shown in formula (I) and the compound as shown in formula (II) to get the siloxane polymer; and (2) preparing the waterborne polyurethane elastic dispersion, wherein the raw material comprises the siloxane polymer obtained in the step (1). After the elastic polyurethane dispersion provided by the invention forms a film, the waterborne polyurethane elastic dispersion has not only excellent tensile strength, rebound elasticity, wear resistance, water resistance and ethanol tolerance, but also soft and smooth hand feeling and high light transmission; and an additional filler is not required, a product has high light extinction or frosted appearance by only adjusting components, after the film is formed, the elastic polyurethane dispersion is soft, and the elastic polyurethane dispersion is suitable for paper, cloth, leather and other soft substrates, and the preparation process is simple and easy to operate.

The invention provides a double-channel light cavity ring-down atmospheric aerosol extinction instrument and an extinction factor measuring method. According to the extinction instrument, utilizes a double-channel light cavity ring-down spectrum technology is applied to carry out in-situ real-time measurement on an extinction factor of atmospheric aerosol. The instrument comprises a light path system, a circuit system and a gas path system, wherein the light path system is internally provided with a first light cavity and a second light cavity, and the first light cavity and the second light cavity are utilized as double channels; and the gas path system respectively provides atmospheric gas and background atmospheric gas containing the aerosol for the first light cavity and the second light cavity, the circuit system can eliminate the transformation of the extinction factor of the aerosol caused by gas change in real time, and the extinction factor value of the atmospheric aerosol is accurately measured in a real time.

The present invention relates to an optical power and extinction ratio controlling device and method. An optical signal output from a light source is detected and optical power and extinction ratio of the light source are controlled. In detail, a feedback signal is provided to the light source to automatically control the bias current based on a DC signal output by a photodetector detecting the optical signal. Therefore, the optical output of the light source is maintained. Also, an optical signal output by the photodetector is converted into a predetermined times DC signal, and a feedback signal is provided to the light source to automatically control the modulation current based on the DC signal. Therefore, the extinction ratio of the light source is maintained. As a result, the extinction ratio is automatically maintained to satisfy the change of condition and the characteristic of light source, thereby maintaining quality optical outputs.

The invention relates to a premix burner with high flame stability for use in a heat generator, preferably in the combustion chamber of a gas turbine. Modern, lean-operated premix burners enable very low noxious emissions, but sometimes operate very close to the extinction limit. To increase the stability of the lean premix combustion by increasing the distance between flame temperature and extinction limit temperature the invention proposes to equip the burner in the mixing zone (200) with a net-like structure (201) for the premixing of combustion air and fuel. According to a preferred embodiment, the net-like structure (201) consists of a plurality of layers of individual wire mesh fabrics (202) arranged at a distance from each other. The wire mesh fabrics (202) are preferably equipped with an oxidation-promoting, catalytically active surface. It was found that the net structure (201) positively influences the thermoacoustic behavior of the burner and dampens and insulates pressure waves from the combustion chamber (300), and in this way reduces the excitation of pressure waves in the combustion chamber (300).

The invention relates to a multi-parameter adjustable spray flow experimental system which comprises an air source module, a flow control valve, a vortex flow meter, a water storage tank, a metering pump, a frequency converter, an atomizing and mixing section, a liquid film collection device, a light extinction granulometer and a throttling valve, wherein air provided by the air source module is fed into the atomizing and mixing section via the flow control valve, and the gas phase flow rate is metered by the vortex flow meter; water provided by the water storage tank is adjusted by the metering pump and the frequency converter and then atomized by a high-pressure nozzle so as to form micro-scale droplets to enter the atomizing and mixing section, the water flow is controlled by the metering pump, the metering pump is used for performing flow control by virtue of a combination of two manners such as frequency modulation and stroke adjustment, and the frequency is continuously adjustedby the frequency converter; and after forming the spray flow on the atomizing and mixing section, the gas phase and the liquid phase enter the liquid film collection device, and by virtue of control and measurement of gas displacement by the throttling valve, the particle size and concentration of droplets in the pipeline are measured by the light extinction granulometer via the liquid film collection device.

The invention discloses a control device of the bias voltage of an electro-optical intensity modulator for quantum private communication and a control method thereof. The control device is a high-accuracy closed-loop control device. The output of the electro-optical intensity modulator is converted into electric signals by an optical detector; and low-frequency signals for direct-current point drifting are extracted by utilizing a lock-in amplifier circuit module. The invention has the advantages that the drifting condition is monitored by a microprocessor, so that the circuit module is driven to change the bias voltage of the electro-optical intensity modulator, and the electro-optical intensity modulator is positioned at a proper working point. The control device has the advantages that the automatic control of the bias voltage of the electro-optical intensity modulator is realized, so that the electro-optical intensity modulator can work continuously by stable extinction ratio, and the working stability of the system for the quantum private communication is improved.

The invention provides a composite structure based on metamaterials and semiconductor low dimension quantum materials. The composite structure based on the metamaterials and the semiconductor low dimension quantum materials is composed of a substrate (1), a buffer layer (2), the semiconductor low dimension quantum materials (3), semiconductor interlayer materials (4) and the metamaterials (5). The metamaterials (5) is in the structure of cycle-assigned metal wire arrays, cycle-assigned metal opening resonance ring arrays or a fishing net. The thickness of the semiconductor interlayer materials (4) is 5 to 50 nanometers. According to the composite structure based on the metamaterials and the semiconductor low dimension quantum materials, a light gain property of the semiconductor low dimension quantum materials and a high speed response property of semiconductor materials to a light signal are simultaneously used, and the composite structure based on the metamaterials and the semiconductor low dimension quantum materials has the dual functions of compensating metamaterial wastage and regulating and controlling metamaterial properties. Under the condition that control light or pump light is additionally arranged, according to the composite structure based on the metamaterials and the semiconductor low dimension quantum materials, the functions of full light opening and closing or full light wavelength conversion can be achieved, and the composite structure based on the metamaterials and the semiconductor low dimension quantum materials has the advantage of being large in extinction ratio.

The present invention addresses the problem of transmitting optical signals with high extinction ratios using low-power drive signals. At present, low-power optical transmitters typically operate with modulation extinction ratios of, at best, about 10 dB. Embodiments of the present invention may achieve extinction ratios exceeding 20 dB using low-power drive signals of under 20 mW at data rates on the order of Gbits/sec. In addition, the modulation may be achieved with both low-power and low-fidelity drive waveforms, enabling conventional and often noisy high-speed, low-power electronics to generate high-extinction, high-fidelity optical waveforms.