601results about How to "High extinction ratio" patented technology

The present invention provide an optical circuit device having: an optical circuit; a polarization beam splitter/combiner for splitting an incoming light beam into two polarization beams and combining the two polarization beams into an outgoing light beam; a first optical waveguide and a second optical waveguide for connecting the optical circuit and the polarization beam splitter/combiner and receiving the two polarization beams independently; and a polarization rotator, arranged on the first optical waveguide, for rotating a polarization plane of one of the two polarization beams split by the polarization beam splitter/combiner so as to match a polarization plane of the other of the two polarization beams, the optical circuit, the polarization beam splitter/combiner, the first optical waveguide, the second optical waveguide and the polarization rotator being integrated on a planar substrate.

This invention relates to apparatus and methods for sensing terahertz radiation, in particular over an area, and to terahertz radiation imaging systems. A terahertz radiation sensor, the sensor comprising an optical beam input to receive an optical probe beam, a detector to modulate said probe beam responsive to terahertz radiation, and a photosensitive detector to provide an output responsive to said probe beam modulation. The sensor being configured to provide a first optical path between said optical beam input and said electro-optic detector and to provide a second optical path between said electro-optic detector and said photosensitive detector, and wherein said sensor further comprises a polarizer, said polarizer being located in both said first and said second optical paths. We further describe imaging systems for use with such a probe.

The invention discloses a polaroid sheet with a subwavelength grating structure, which comprises a transparent substrate, a dielectric grating, a first metal layer and a second metal layer. The dielectric grating is provided with ridges and grooves which are periodically arranged at intervals, the first metal layer is covered on the ridges of the dielectric grating, the second metal layer is covered in the grooves of the dielectric grating, and the period of the dielectric grating is less than the wavelength of incident light. The invention is characterized in that: a high refractive index dielectric layer is arranged between the transparent substrate and the dielectric grating, and the refractive index of the high refractive index dielectric layer is between 1.6 and 2.4. The transmission efficiency and the extinction ratio of TM light of the polaroid sheet are improved by adding the high refractive index dielectric layer between the transparent substrate and the dielectric grating. In the whole visible light waveband, the polaroid sheet has high transmission efficiency, high extinction ratio, and wide incident angle range. In the process, a nano-imprint technique is adopted to process and produce, the production process is simple and convenient and is easy to operate, an etching process is not needed, and the processing cost is reduced.

The making process of lithium niobate modulator includes making substrate with lithium niobate crystal with proper crystal cutting direction and electric field utilizing direction; making light waveguide on the lithium niobate crystal; making modulating electrodes including central signal electrode and earth electrode and to form push-pull structure with the light waveguide; making microstrip matching structure in the input and output of the modulating electrodes; and setting buffering layer structure between the modulating electrode and light waveguide. Owing to the smart design of the modulating electrodes, the light waveguide and the matching structure in between, the lithium niobate modulator has high modulating rate, low insertion loss, high extinction ratio, low hemi-wave voltage, less electric reflection, and high reliability.

The invention discloses a micro-polarizing film array used for acquiring full-polarization parameters and a production method and application thereof. The micro-polarizing film comprises a plurality of micro-polarizing film units with size of 2*2. Each micro-polarizing film unit comprises a micro-polarizing film of 0 degree, a micro-polarizing film of 45 degrees, a circular micro-polarizing film and a micro-polarizing film of 90 degrees which are closely integrated on the same plane and further sequentially disposed from the top left corner in a clockwise manner. The micro-polarizing film array is easy to produce and high in polarizing light transmittance performance and integration level.

The invention relates to a silicon nitride-lithium niobate heterogeneous integrated waveguide device structure and a preparation method of the same. The silicon nitride-lithium niobate heterogeneous integrated waveguide device structure is characterized in that a silicon nitride waveguide in a silica coating layer and a lithium niobate film on the upper surface of the silicon nitride waveguide areheterogeneously integrated to form a ridge waveguide; a traveling wave electrode is arranged on the upper surface of the lithium niobate film; the silicon nitride waveguide is crossed and coupled with the lithium niobate film on the upper surface of the silicon nitride waveguide, and a high speed electric signal is applied to the traveling wave electrode to control the phase of the light wave passing through the lithium niobate film to realize conversion from amplitude modulation of the loaded electric signal to phase modulation of an optical signal; and three-dimensional vertical integrateddesign is utilized to enable integration of the chip to be more compact, so that the space is saved; at the same time insertion loss of the light waveguide can be reduced; 100G light modulation rate can be realized; high speed modulation of the light wave in the lithium niobate film can be realized and the characteristic of low loss propagation through the silicon nitride waveguide is realized; and light modulation with excellent performance is completed. The manufacturing technology of the silicon nitride-lithium niobate heterogeneous integrated waveguide device structure is compatible with the semiconductor processing technology, is high in the modulation efficiency and low in energy consumption, and has important application prospects in the optical signal processing field and other fields.

In a Wavelength-Division-Multiplexed Passive Optical Network (WDM-PON) utilizing a conventional downstream optical signal reusing method, there is an inventory problem that different optical transmitter types need to be provided for the operation, management, replacement, etc. of a system. A WDM-PON system according to the present invention, includes: a seed light (SL) unit generating a seed light whose wavelength intervals and center wavelengths are adjusted using at least one seed light source; an optical line terminal (OLT) receiving the wavelength-multiplexed seed light from the seed light unit, transmitting a downstream optical signal to a subscriber of the WDM-PON, and receiving a upstream optical signal from the subscriber; and an optical network unit (ONU) receiving the downstream optical signal from the OLT, flattening and modulating the downstream optical signal with upstream data so that the downstream optical signal is reused for carrying upstream data. It is possible to improve the quality and reliability of downstream transmission by sufficiently increasing an extinction ratio, and improve the quality and reliability of upstream transmission by sufficiently flattening an input downstream optical signal in a semiconductor optical amplifier.

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 invention discloses a single longitudinal-mode optical fiber laser with low noise, narrow linewidth and high power. Polarization maintaining optical fiber is rare-earth-doped phosphate single-mode glass optical fiber, the component of a fiber core is phosphate glass which consists of 70P2O5-8Al2O3-15BaO-4La2O3-3Nd2O3, the fiber core of the polarization maintaining optical fiber is doped with high-concentration luminous ions, the luminous ions are one or combination of more than one of lanthanide ions and transition metal ions, the doping density of the luminous ions is greater than 1*10<19>ions/cm<3> and the luminous ions are evenly doped in the fiber core. A polarization maintaining fiber Bragg grating with the narrow linewidth and a dichroscope form a front cavity mirror and a rear cavity mirror of the optical fiber laser, a centimeter-sized erbium-ytterbium co-doped phosphate glass polarization maintaining optical fiber is taken as a laser working substance, and polarization maintaining output laser generated by a single-mode semiconductor laser is taken as a pumping source, thus achieving the single longitudinal-mode laser output by designing and manufacturing the reflection spectrum width of the polarization maintaining fiber Bragg grating and controlling the cavity length of the whole laser cavity.

The invention discloses a high-linearity degree-of-polarization quantum-well infrared detector with a plasmon micro-cavity coupled structure. The detector is composed of an upper metal grating layer, a quantum-well infrared photovoltaic conversion activating layer and a lower metal reflecting layer, wherein the upper metal grating layer is formed by metal strips. The detector has the advantages that under the mode selection effect of an electromagnetic wave near-field coupled micro cavity formed by plasmon resonance between the upper metal grating layer and the lower metal reflecting layer, photons capable of entering the micro cavity are mainly photons capable of achieving resonance with a detected wavelength polarization mode; the direction of electric vectors of the photons entering the micro cavity is changed to the z direction from the x direction by being modulated in a micro-cavity mode, and the photons can be absorbed by quantum-well sub-bands in a transition mode to achieve the photovoltaic conversion process. With the advantages, the polarization coupled structure can greatly improve the extinction ratio of polarization responses, and extremely-high polarization distinguishing capacity of the detector is achieved.

A broadband optical switch with high process tolerance designed and fabricated using Planar Lightwave Circuits (PLC) technology. A 2x2 configuration of the switch is based on a Mach-Zehnder interferometer (MZI) configuration that includes two 3 dB adiabatic couplers and two identical arms. Each adiabatic coupler is characterized by two straight branches having different widths, separated over a coupling length by a changing spacing therebetween and blending in a symmetric intersection area, which connect to two symmetric branches. The two adiabatic couplers are connected by the two arms with their symmetric branches facing each other along an optical propagation axis. Switch control is realized by changing an optical property of one or both of the MZI arms. Implementation in silica-on-silicon PLCs provides switches with an exceptional broadband range (1.2-1.7 mum), very high extinction ratios (>34 dB), low fabrication sensitivity and polarization independent operation.

This invention provides a polarized component with double-metal layer gratings. Multiple parallel dielectric layers having a period are formed on a transparent base, a groove is set between adjacent dielectric layers, a first metal layer having a first thickness is formed on the groove, a second metal layer with a second thickness and a width formed on the dielectric layer, in which, a vertical distance of 10~100um is between the first and second metal layers to isolate them. The period is 10~250nm, the thickness is 30~150nm, the first is equal to the second. The proportion of width/period is 25~75%. This invention also discloses the manufacturing method.

The invention discloses a micro-ring resonant cavity electro-optical modulator based on a graphene/molybdenum disulfide heterojunction. The micro-ring resonant cavity electro-optical modulator comprises a substrate layer, a direct-light waveguide, a micro-ring resonant cavity waveguide and a graphene covering layer. The direct-light waveguide and the micro-ring resonant cavity waveguide are embedded into the substrate layer, and a coupling space is reserved between the direct-light waveguide and the micro-ring resonant cavity waveguide. The upper surface of the micro-ring resonant cavity waveguide is covered with a part of the graphene covering layer. The graphene covering layer comprises a first graphene layer, a second graphene layer, molybdenum disulfide, a first electrode and a second electrode, wherein the first graphene layer and the second graphene layer are isolated by the molybdenum disulfide, the first graphene layer stretches outwards from one side of the micro-ring resonant cavity waveguide and is connected with the first electrode, and the second graphene layer stretches outwards from the other side of the micro-ring resonant cavity waveguide and is connected with the second electrode. The micro-ring resonant cavity electro-optical modulator has extremely low optical loss, a low thermo-optical coefficient, low insertion loss, large environment temperature tolerance, a good modulation depth and a high extinction ratio.