233 results about "Modulation efficiency" patented technology

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.

The invention discloses a microwave signal phase shifting method based on polarized light interference technique in the technical field of microwave photonics. Photonic microwave signals generated by modulating a single sideband are transmitted by a polarization maintaining fiber and generate a group of optical carrier with locked phase and vertical polarization in a polarization manner by using the high birefringence characteristics and an appointed fusion angle. The input vertically-polarized optical carriers can generate different phase shift under the bias voltage of a phase modulator according to the polarization relativity of the modulation efficiency of the phase modulator, so that the phase difference among the optical carriers can be changed by adjusting the bias voltage. Then, the optical carriers are received by an analyzer with an appointed polarization angle to generate a group of parallel-polarized phase-shifting optical carriers. A photoelectrical detector can generate an electrical domain microwave phase-shifting signals after receiving beat frequency and isolating DC components, wherein the phase shifting magnitude depends on the bias voltage of the phase modulator. The invention further lowers the complexity of the microwave phase shifting system, and improves the phase shifting accuracy.

The present invention discloses a Mach-Zehnder type silica optical waveguide switch based on narrow slit waveguide. After the wave splitting of the 3dB coupler which realizes power splitting function at the input end, a first group of two spot-size converting structures are respectively connected to the interference arms of two narrow slit waveguide structures, and then are connected to the output-end interference coupler through a second group of two spot-size converting structures. A random-structure 1*2 and 2*2 optical switches are formed through the different combination of two groups of spot-size converting structures. The present invention leads to a narrow slit waveguide and fills a low refraction ratio electrooptic material in the narrow slit. The modulation facility is enlarged, and the conventional indirect electrooptic modulation of carrier injection is switched to a direct electrooptic modulation. Besides, the silicon waveguides which are at two sides of the narrow slit and are electrically insulated naturally are taken as electrodes and the distance from the electrode to the modulation area is shortened. The two characteristics can equally increase the modulation efficiency of the switch. The whole structure is compact in dimension. The invention is compatible to the CMOS processing technique and provides a novel approach for the realization of the single-chip integrated high-speed electrooptic switch.

A portable electronic device that has a radio frequency communication subsystem operationally connected switch-mode power supply subsystem. The switch-mode power supply subsystem generates a pulse-width modulation electrical signal that produces electromagnetic interference. The switch-mode power supply subsystem can reduce the slew rate of the pulse-width modulation electrical signal when the radio-frequency communication subsystem is active. This reduces the level of the electromagnetic interference signal only during radio frequency communication, which improves the efficiency of the radio frequency communication. Not having the reduced slew rate when there is no radio frequency communication allows for higher modulation efficiency.

The invention relates to Y-branch waveguide dual optical phase modulators with improved electro-optic (EO) frequency and step responses at frequencies below 1 Hz for use in low-frequency applications such fiber-optic gyroscopes. A Y-branch waveguide structure is formed in an EO substrate, with three or more electrodes used to form a waveguide phase modulator in each of two output waveguide arms. In one embodiment an insulating buffer layer is provided between at least a portion of the electrodes and the substrate for flattening the low-frequency EO response by reducing the modulation efficiency below 1 Hz. In one embodiment each of the waveguide phase modulators includes two ground electrodes extending along both sides of a signal electrode. A top portion of the substrate may be doped to reduce lateral variations of the substrate conductivity in the waveguide and non-waveguide portions thereof between corresponding signal and ground electrodes.

A display device and modulation scheme for applying image data to an imager. The display may use a modulation scheme wherein spacing of row write actions on the rows creates gray scale modulation, wherein one row spacing between sequential row write actions is at a first distance while another row spacing between sequential row write actions is at a distance greater than said first distance. The modulation scheme may create a series of write pointers that create a corresponding series of write planes. In some embodiments, modulation efficiency is increased allowing the use of lower frequency imaging circuits to achieve the same display image.

The present invention provides a spread spectrum type clock generation circuit whose EMI for peripheral equipment is reduced. The clock generation circuit comprises a phase-locked loop circuit and a clock modulation circuit. The clock modulation circuit comprises a ΔΣ modulator, to frequency-modulate an output clock by modulating the frequency division number of a frequency divider in the phase-locked loop circuit by a digital circuit, and further comprises a modulation pattern controller for distributing the peak of a triangular waveform which is a modulation waveform generated by a modulation pattern generator to change the amplitude and the period thereof, thereby making it possible to eliminate dullness and distortion of a modulation waveform in a modulating method using a conventional analog circuit and to obtain an output clock having higher modulation efficiency than that in a case where a normal triangular waveform is employed in a conventional modulating method using a digital circuit.

The invention discloses a direct modulation distributed feedback semiconductor laser-based photoelectric oscillator. The characteristic that a semiconductor laser has maximum modulation efficiency at relaxation oscillation frequency is utilized, and a distributed feedback semiconductor laser is used for simultaneously realizing photoelectric conversion and photonic microwave filtering functions without an additional electro-optic modulator and an additional narrow-band electric filter. The relaxation oscillation frequency of the laser is tuned by tuning the bias current and the working temperature of the laser to finally realize the large-range frequency tuning of the photoelectric oscillator.

A silicon-based optical modulator exhibiting improved modulation efficiency and control of “chirp” (i.e., time-varying optical phase) is provided by separately biasing a selected, first region of the modulating device (e.g., the polysilicon region, defined as the common node). In particular, the common node is biased to shift the voltage swing of the silicon-based optical modulator into its accumulation region, which exhibits a larger change in phase as a function of applied voltage (larger OMA) and improved extinction ratio. The response in the accumulation region is also relatively linear, allowing for the chirp to be more easily controlled. The electrical modulation input signal (and its inverse) are applied as separate inputs to the second region (e.g., the SOI region) of each arm of the modulator.

The invention comprises: a substrate; a silica buried layer formed on the substrate; a p type monocrystalline silicon layer is uses as the monocrystalline silicon on the substrate; forming a grid oxide layer on both sides of the p type monocrystalline silicon layer; a p+ injection layer is formed on the p type monocrystalline silicon layer; a n type monocrystalline silicon layer is formed on the silica buried layer and the both sides of the grid oxide layer, and said n type monocrystalline silicon layer and p type monocrystalline silicon layer are combined together to form a ridge waveguide structure; a n+ injection layer formed on the planes at both sides of the n type monocrystalline silicon ridge waveguide structure; a metal contact layer is formed on middle portion of the p+ injection layer in order to form the positive and negative electrode of the modulator; a oxide layer formed on the surfaces of the n type monocrystalline silicon layer and p type monocrystalline silicon as a protective layer.

The invention relates to a doping structure of a silicon-substrate electrooptical modulator. The doping structure comprises a silicon-substrate electrooptical modulator modulating region waveguide, and the waveguide sequentially comprises a first heavily-doped region, a second lightly-doped region, a third lightly-doped region and a fourth heavily-doped region in the transverse direction which is perpendicular to the extending direction of a protruding strip region of the waveguide. The second lightly-doped region and the third lightly-doped region form at least one longitudinal PN junction and at least one transverse PN junction, and the longitudinal direction is perpendicular to the transverse direction. The second lightly-doped region is in electric connection through the first heavily-doped region, and the third lightly-doped region is in electric connection through the fourth heavily-doped region. By means of the doping structure of the silicon-substrate electrooptical modulator, modulation energy consumption can be reduced while the modulation efficiency of the silicon-substrate electrooptical modulator is improved, each doped region of a waveguide core region can directly achieve electric connection through a lateral waveguide, and the high-speed modulation performance of the system is ensured.

The invention relates to the field of integrated optics, in particular to a lithium niobate thick film-based high-speed electro-optical modulator and a preparation method thereof; the modulator comprises a supporting substrate, a bonding layer, an optical waveguide and a modulation electrode, wherein the optical waveguide is located on the surface of the bonding layer, and a layer of lithium niobate thick film is arranged on the bonding layer; the thickness of the lithium niobate thick film is 8-20 microns; by virtue of about 10 microns of the ridge height of the thick-film lithium niobate, the modulation efficiency can be improved by 60% or above, and the substrate is only 8-20 microns in thickness due to the thinning technology, so that the resonance effect can be avoided, and the high-speed broadband can be further realized; and compared with a thin film type waveform lithium niobate modulator, the lithium niobate thick film-based high-speed electro-optical modulator has the advantages of being low in diffusion type optical waveguide transmission loss and low in coupling loss.

The invention discloses a silicon-nitride three-dimensional integrated multi-micro-cavity resonant filter, and the filter comprises a feedback waveguide which is coated with silicon dioxide and is located at the upper layer, an integrated sub-micro-ring structure, and a micro-ring resonant cavity located at the bottom layer, wherein the feedback waveguide at the upper layer interacts with the micro-ring resonant cavity at the bottom layer, so as to divide the light of the same light source into two beams in a device and enable the two beams to be resonant for output at an output port, therebyobtaining a compact filtering effect. A metal heating electrode is attached above the micro-ring resonant cavity, thereby achieving the switching of the amplitude modulation of a loaded electric signal to the phase modulation of an optical signal. The invention also discloses a preparation method for the silicon-nitride three-dimensional integrated multi-micro-cavity resonant filter. A three-dimensional vertical integrated design enables chips to be integrated more compactly, and reduces the insertion loss of an optical waveguide. The manufacturing technology is compatible with the semiconductor processing technology. The modulation efficiency is high, and the energy consumption is low. The filter can be produced in batch at low cost, and the filter is good in application prospect in the field of optical signal processing.

An optical modulator is provided with a stripe-shaped optical waveguide, which has an upper clad layer, a lower clad layer formed between the upper clad layer and a substrate, and an undoped core layer which is arranged between the upper clad layer and the lower clad layer and has a complex refractive index that changes corresponding to the intensity of an applied electric field, to a signal light propagating inside. On the both sides of the stripe-shaped optical waveguide, conductor walls are configured by arranging a pair of parallel blocking flat boards with an insulating wall in between. Thus, the semiconductor optical modulator having a high optical modulation efficiency is provided

A high-speed optical modulator based on Surface Plasmon-Polariton (SPP) at the hetero-junction of a metal-insulator-semiconductor (MIS) tunneling diode and including a phase-matching optical element, such as a prism or gold-lattice structure, is described. An investigation using the coupled mode theory shows that the applied bias across the hetero-junction changes the optical reflectance of an optically coupled MIS tunneling diode, such as a prism-coupled MIS tunneling diode or a gold lattice-coupled MIS tunneling diode, while the modulation efficiency achievable of the device depends on the thickness of the metal film used to construct the tunneling diode.

The invention relates to a preparation method of an environmentally-friendly thermochromic vanadium dioxide film. The preparation method comprises the followings steps: 1) dissolving vanadium pentoxide and ascorbic acid in deionized water to obtain a uniform solution, adding concentrated hydrochloric acid until the solution reacts to become dark brown and green, then heating in a water bath and stirring until the solution is blue and transparent, then adding polyvinylpyrrolidone, and stirring at room temperature to obtain a precursor sol; 2) spin-coating the precursor sol on the surface of a quartz glass substrate by adopting a spin-coating method to prepare a film, then drying the quartz glass substrate, and finally putting the quartz glass substrate in a high temperature furnace for annealing treatment so as to obtain the thermochromic vanadium dioxide film. The vanadium pentoxide is reduced by adopting non-toxic ascorbic acid with relatively high reducibility, and the vanadium dioxide film with uniform particle size, large porosity, relatively high visible light transmittance and sunlight modulation efficiency is obtained by adjusting the proportion of initial reactants, the concentration of the precursor sol and the addition of the concentrated hydrochloric acid.

The invention discloses a PN junction. The PN junction at least comprises light-doped P regions and light-doped N regions connected with the light-doped P regions, wherein the light-doped P regions and the light-doped N regions are alternately distributed in the length direction of a waveguide ridge region, and the projection of the interface between the light-doped P regions and the light-doped N regions on the waveguide ridge region on the plane perpendicular to the interface is a broken line. By means of the scheme, modulation efficiency is improved, and power consumption is reduced.

An optical waveguide device is disclosed wherein the modulation efficiency for a driving voltage is improved. The optical waveguide device includes a substrate having an electro-optic effect, an optical waveguide formed on the substrate, an electrode section adapted to supply an electric field for carrying out phase modulation synchronized with a clock signal to the optical waveguide, and a Mach-Zehnder interferometer connected to the downstream side of the optical waveguide and including two branching waveguides having optical lengths different from each other.

The invention discloses a low-drive-voltage lithium niobateelectrooptical modulator. A ridge waveguide structure is made on an X-cut Y-pass lithium niobate crystal, and the electrode structures of theelectrooptical modulator are made on two sides of the ridge waveguide structure, so that the electric field between the electrode structures of the electrooptical modulator can be distributed along the horizontal direction. Compared with existing lithium niobateelectrooptical modulator, the lithium niobateelectrooptical modulator disclosed by the invention has the advantages that the modulation efficiency of an optical field can be remarkably improved by an electric field, and the drive voltage of a device is reduced. In other schemes, a low-dielectric-constant material can be adopted as a substrate wafer of a lithium niobate film, and the ridge waveguide structure is made on the lithium niobate film, thus the working bandwidth of the lithium niobateelectrooptical modulator can be effectively increased, and the drive voltage of the lithium niobateelectrooptical modulator can be lowered. The invention also provides a manufacturing method of the low-drive-voltage lithium niobateelectrooptical modulator.

The invention discloses an electrooptical modulator which comprises mode spot converters, Y-branch beam splitting optical waveguide, Y-branch beam combining optical waveguide, hybrid integration phasemodulation arms and travelling wave electrodes, wherein the mode spot converters are used for reducing mode field mismatching of single-mode optical fibers and the modulator and realizing high-efficiency coupling of optical fields of the single-mode optical fibers and the modulator; the Y-branch beam splitting optical waveguide is used for splitting a laser beam to form beam splitting laser; thehybrid integration phase modulation arms are used for transmitting laser, converting optical mode fields and realizing high-efficiency modulation of an electrical signal to an optical signal; the travelling wave electrodes facilitate realization of speed matching of optical wave and microwave, and further improve the band width of the modulator; and the Y-branch beam combining optical waveguide isused for combining the modulated beam splitting laser into a laser beam. The modulator integrates the mode spot converters, so that the coupling loss of the optical fields from the optical fibers tothe modulator is greatly reduced; and the insertion loss of the modulator is reduced. The modulator can obviously improve the electrooptical modulation efficiency, so that the half-wave voltage of themodulator can be reduced.

The invention is applicable to an electro-optic modulator, and provides an electro-optic modulator and a preparation method thereof. The electro-optic modulator comprises a low refractive index substrate layer, a first graphene electrode, a second graphene electrode, a first metal electrode formed on the first graphene electrode, a second metal electrode formed on the second graphene electrode, ahigh electro-optic coefficient optical waveguide formed on the substrate layer and a low refractive index covering layer covering the high electro-optic coefficient optical waveguide, wherein the first graphene electrode and the second graphene electrode are formed on the substrate layer; and the first graphene electrode and the second graphene electrode are attached to the two sides of the high electro-optic coefficient optical waveguide respectively. By implementation of the electro-optic modulator, not only can the electro-optic modulator be miniaturized, but also the electro-optical modulation efficiency can be improved.

The invention relates to the technical field of optical modulators, and particularly relates to an optical waveguide modulator. The optical waveguide modulator comprises a modulation area, a wavelength selection area and a connection area, wherein the modulation area is in a resonant cavity structure and used for changing the refractive index of an optical waveguide through a physical reaction, and a nonlinear relation is formed between the refractive index and phase change of the optical waveguide; the wavelength selection area is in a closed optical waveguide structure and used for carrying out selection on resonance wavelengths by using an interference method; and the modulation area and the wavelength selection area are subjected to optical signal transmission by the connection area. By using the the optical waveguide modulator provided by the invention, a nonlinear change relation between a refractive index and a coupling coefficient can be realized by a special coupling structure, and the reduction on the size of the modulator can be realized while high-efficiency coupling regulation is carried out. Compared with the existing optical waveguide modulator, the modulation efficiency ratio of the optical waveguide modulator provided by the invention is over 10 times as large as the existing optical waveguide modulator; and because the modulation area is isolated from the wavelength selection area, the drift influence (caused by an active thermal effect) on operation wavelengths is reduced.