163results about How to "Achieve tuning" patented technology

The invention relates to a magnetic control tunable optical fiber comb filter belonging to the technical fields of optical fiber sensing and optical fiber communication. The magnetic control tunable optical fiber comb filter comprises a broadband light source, an optical fiber coupler, an optical fiber environment, a magnetic field generating unit and a photoelectric detector, wherein the optical fiber environment comprises a left arm optical fiber, a right arm optical fiber and a PCFG (Photonic Crystal Fiber Grating). The magnetic control tunable optical fiber comb filter is characterized in that the PCFG cladding is provided with five large shaddock-form air holes of single-layer structures, and magnetofluid is filled into the large air holes through a capillary phenomenon and changes in the refraction index under the action of a variable magnetic field to change the effective refraction index of a PCFG cladding and cause the wavelength movement of a harmonic peak coupled between a PCFG base mode and a cladding mode so as to realize the tunability as the output characteristics of the filter. Because of different lengths of the left arm optical fiber and the right arm optical fiber in the optical fiber environment, two paths of light signals reflected by the PCFG have a light path difference and are subjected to interferences when returning to the optical fiber coupler so that a comb filter effect is generated in an output spectrum of the filter.

The invention discloses a package structure and package method of an integrated tunable antenna array and a radio frequency module. The package structure comprises a rigid-flexible board and a radio frequency module package body, wherein the rigid-flexible board is used for arranging an antenna array patch, the radio frequency module package body is used for packaging a radio frequency chip, the rigid-flexible board and the radio frequency module package body are vertically and oppositely arranged and are fastened by four bolts and nuts, the four bolts and nuts are arranged at corners and arematched, and the rigid-flexible board is fixedly connected with one side of the radio frequency module package body by a second flexible substrate. With the package structure of the integrated tunableantenna array and the radio frequency module, fabricated by the invention, the integration of the integrated tunable antenna array and the radio frequency module is achieved, moreover, the tuning ofthe antenna array also can be achieved, the package structure has the characteristics of high integration, good electromagnetic shielding effect, antenna gain, high radiation efficiency, small radiation power and low loss, and the demands of different application occasions can be satisfied.

The invention belongs to an optical add/drop filter, and particular relates to a microminiature optical add/drop filter based on a two-dimensional photonic crystal. The invention is characterized in that the optical add/drop filter comprises an upper end direct waveguide, a lower end direct waveguide and an autocollimating ring zone; the electromagnetic field energy of the upper end direct waveguide and the lower end direct waveguide are coupled to further form a resonant cavity by a photonic crystal ring zone; the range of the frequency or wavelength of photonic crystal autocollimating work is covered by an upper end waveguide working zone. The upper end direct waveguide and the lower end direct waveguide consist of dielectric column type photonic crystal arrays which are arranged by tetragonal lattices with line defects, and also consist of a photonic crystal arrays which are arranged by triangular lattices with line defects or two-dimensional plates with line defects. The photonic crystal autocollimating ring zone forms a photonic crystal autocollimating microring by adjusting the size of the radius of the photonic crystal of the ring zone under the limitation of an external photonic crystal band gap. The microminiature optical add/drop filter has more compact structure and simpler design and is applicable to optical communication and optical sensing system.

The invention discloses a distributed Bragg reflector (DBR)-based external cavity wavelength-tunable laser, which comprises an active photonic chip. An optical waveguide is arranged in the photonic chip, and comprises a gain section and a reflection grating section. The two sides of each section are provided with a corresponding electrode respectively. An optical lens, an optical etalon and a reflector are sequentially arranged on one side an optical waveguide port from which the emitted light of a reflection grating is derived, and form a passive external cavity feedback area which forms a laser resonant cavity with the photonic chip. Photons obtain maximum feedback at an overlapped wavelength by changing the comb maximum reflection peak distribution of the reflection grating section or simultaneously changing the comb maximum reflection peak distribution and the maximum transmission peak distribution of the optical etalon to realize the stepped or continuous tuning of output laser wavelengths and changing the output laser wavelengths within a relatively wider range.

The invention relates to the down-link structure of a millimeter-wave fibre-optic transmission system and a method for generating millimeter waves with tunable frequencies. In the down-link structure of the millimeter-wave fibre-optic transmission system, double lasing light emitters are arranged in a key station, a first light wave passes through a double electrode Mach-Zehnder modulator, and a light carrier which carries digital baseband signals and comb spectral components which are spaced by the frequency of radio-frequency signals are generated at the output end of the modulator. A second light wave which passes through a circulator is taken as pump light and is injected into a polarization-preserving fiber in a reverse direction, the frequency of the second light wave is changed so as to amplify the comb spectral components of corresponding frequency points in the first light wave through stimulated Brillouin effect, and millimeter-wave signals with the corresponding frequencies can be generated at a photodetector on a base station. As the millimeter-wave signals are modulated by the digital baseband signals, the down transmission of information needed from the key station to the base station is realized. The RoF down-link has simple structure and realizes the purpose of simultaneously transmitting the digital baseband signals and the radio-frequency signals by utilizing one double electrode Mach-Zehnder photomodulator.

The invention relates to an intelligent excitation control system for a generator set. The system includes a voltage detection unit, a data processing unit, a PID calculation unit, a power amplification unit and an intelligent instruction list, wherein the intelligent instruction list is used for determining PID parameters of the PID calculation unit and stores a plurality of sets of instructions, and each set of instruction consists of a preset voltage deviation value, a preset voltage deviation change rate and corresponding PID parameters; and an intelligent control unit is used for receiving information of a voltage deviation value e and a voltage deviation change rate ec, and judging whether difference value rates of the voltage deviation value e and the voltage deviation change rate ec and the preset voltage deviation value and the preset voltage deviation change rate in the intelligent instruction list are lower than preset different value rates, if yes, the PID parameters in the instruction are input to the PID calculation unit, and if no, an instruction with the sum of the abovementioned two difference value rates being minimum is selected, and the PID parameters in the instruction are input to the PID calculation unit. The system has a relatively good excitation control effect.

The invention provides a band-shaped beam klystron outer tuning apparatus. The apparatus comprises an accommodation cavity, a tuning assembly, a trapezoid lever bracket and a control assembly. An inductance tuning mode is adopted, and a tuning piston is inserted into a band-shaped beam klystron tube body to form a cavity wall of a resonant cavity; and the motion of the tuning piston is controlled through a lever principle so as to change the size and distribution inductance of the resonant cavity and further change the resonant frequency of the resonant cavity. According to the invention, a flexible seal membrane sheet rather than a corrugated pipe is adopted for realizing tuning of the resonant cavity so that the cost is reduced, and the structure is simplified.

The invention discloses a semiconductor laser-pumped kerr lens mode-locked titanium sapphire laser, which comprises first semiconductor lasers, a resonant cavity, an interferometer and a feedback regulation unit, wherein the first semiconductor lasers are used for emitting continuous laser light of blue and green bands to pump titanium sapphire crystal in the resonant cavity; the resonant cavity is used for carrying out oscillating and mode locking on the laser light of near-infrared bands to output femtosecond pulse laser light; the interferometer is used for driving the femtosecond pulse laser light to generate a beat note signal to obtain a carrier-envelope offset frequency; and the feedback regulation unit is used for regulating front and back positions and gradients of end mirrors ofthe resonant cavity and the power of the laser light output by the semiconductor lasers, thereby keeping the stability of a repetition frequency and the carrier-envelope offset frequency. An ultrashort laser light pulse with stable repetition frequency and carrier-envelope offset frequency can be output, and the semiconductor lasers are directly adopted as pumping sources, so that the cost of thelasers is greatly reduced, and the volume of the whole lasers is further reduced.

The invention discloses a terahertz metamaterial waver absorber with a proactively tunable frequency and a manufacturing method thereof. The wave absorber comprises a bottom structure, an intermediatedielectric layer and a top resonant structure. The bottom structure includes at least one metal film. The intermediate dielectric layer is fixed to the bottom structure. The top resonant structure isfixed to the intermediate dielectric layer, and includes a plurality of metal resonant structures arranged in an array. The plurality of metal resonant structures are fixed to the same end surface ofthe intermediate dielectric layer away from the bottom structure. A resonant cavity is disposed in each of the metal resonant structures. Each resonant cavity and the corresponding metal resonant structure are in a cross shape and have a coincident center. Both the metal film and the metal resonant structures are made of copper. The intermediate dielectric layer is made of a flexible PDMS material. Each resonant cavity is filled with a SrTiO3 material. The waver absorber realizes control of incident electromagnetic waves, tunes the wave absorbing frequency of the metamaterial in a large range, and overcomes the limitation of the passive tuning method of the wave absorbing property of the metamaterial.

The invention provides a device and a method for tuning echo wall micro-cavities. The device comprises an optical fiber. The echo wall micro-cavities which are positioned on a side of a fiber core are arranged in cladding of the optical fiber, graphene is laid at cavity openings of the echo wall micro-cavities and is connected with electrodes, and voltages are applied to the graphene by the electrodes, so that the echo wall micro-cavities can be tuned. The device and the method have the advantages that the echo wall micro-cavities are integrated in the optical fiber, the fiber core in the optical fiber is used as waveguide for exciting the echo wall micro-cavities, and accordingly the device is compact and stable in structure; distances between the echo wall micro-cavities and the waveguide for exciting the echo wall micro-cavities rarely change in tuning procedures, accordingly, the device and the method rarely affect quality factors of the echo wall micro-cavities, and the tuning accuracy of the echo wall micro-cavities can be improved; only input laser devices are required in the tuning procedures, extra laser devices can be omitted, and accordingly the device and the method are low in tuning cost; the graphene is extremely high in heat conductivity, heat generated by the graphene can be quickly transmitted to the echo wall micro-cavities, and accordingly the device and the method are high in tuning efficiency.

The invention discloses a broadband active inductor with high Q values and a coarsely tunable and finely tunable inductance value. The broadband active inductor comprises a first transconductance unit (1), a modulation unit (2), a second transconductance unit (3), a third transconductance unit (4), a fourth transconductance unit (5), a first tunable bias circuit (6), a second tunable bias circuit (7), a third tunable bias circuit (8) and a fourth tunable bias circuit (9). The modulation unit is connected with the first transconductance unit and is used for increasing the Q values and bandwidth of the active inductor. The first transconductance unit, the modulation unit and the second transconductance unit form a master circuit. The third transconductance unit and the fourth transconductance unit form a slave circuit. The master circuit and the slave circuit are connected in parallel. The equivalent capacitance for synthesizing the inductance in the whole circuit is increased, so the inductance value of the active inductor is improved. According to the active inductor, the high Q peaks of the active inductor under different frequencies are realized, the Q peaks can be tuned, and the inductance value of the active inductor is coarsely tuned and finely tuned.

The invention discloses an incubation room temperature control method based on cat group optimization and immune fuzzy PID, the temperature of an incubation room serves as a controlled object, a temperature physical model of the incubation room is established through a transfer function, a control rule table, a fuzzy theory domain, a fuzzy language value and a subordinating degree function of a fuzzy ID controller algorithm are designed to realize setting of an integral coefficient and a differential coefficient; a fuzzy reasoning is used for approximating the inhibition amount of cells in animmune algorithm, an immune control rule is determined, an immune control rule, a fuzzy theory domain, a fuzzy language value and a subordinating degree function of an immune P controller algorithm are designed to realize setting of a proportion coefficient; a cat group optimization algorithm is used for intelligent optimization of values of a quantification factor a scale factor of the immune P controller algorithm to determine optimal values of the quantization factor and the scale factor; the temperature of the incubation room can be accurately controlled, the incubation room temperature control method has good dynamic and static performance, is small in overshoot, and fast in adjusting time, and the self-setting of PID parameters is realized quickly and efficiently.

The invention relates to a grey cosine distribution optical target simulation device for MTF (modulation transfer function) detection and belongs to the technical field of image quality assessment of an optical system. The device comprises a lighting source, a narrow band filter, a flat field microobjective, a pinhole reticle, a first optical alignment system, a polarization beam splitter, a variable optical density board, a first standard plane mirror, a second standard plane mirror, a beam splitter, a calibration camera, a coupling objective, a second optical alignment system, a high-precision displacement adjustment table and a controller. The grey cosine distribution optical target simulation device for modulation transfer function detection can accurately simulate a grey cosine distribution target with the space frequency and modulation degree matched with those of a to-be-detected optical system, the grey cosine distribution target is input for MTF detection of the to-be-detected optical system, which accords with the original definition of MTF, besides, MTF of the to-be-detected optical system can be directly measured, follow-up data processing is not required, and accordingly, the precision and the efficiency of MTF detection are improved.

The invention discloses a multi-wavelength optical fiber filter, comprising a first single mode optical fiber, a second single mode optical fiber, a photonic crystal optical fiber and a temperature control module; one end of the first single mode optical fiber is connected with one end of the photonic crystal optical fiber for inputting light beams; one end of the second single mode optical fiber is connected with the other end of the photonic crystal optical fiber for outputting the light beams; the temperature control module is attached to the side wall of the photonic crystal optical fiber for regulating and controlling the temperature of the photonic crystal optical fiber and realizing the tuning on the multi-wavelength optical fiber filter in the free-spectrum range; an organic matter layer for enhancing the thermal sensitive property of the photonic crystal optical fiber is filled in air holes of the photonic crystal optical fiber. The multi-wavelength optical fiber filer has the characteristics of flexible and adjustable free spectrum range and flat top of transmitted spectrum.

The invention concretely discloses a surface-enhanced optical spectrum underlay of an unsymmetrical double-split ring, belonging to the technical field of surface optical spectrum. The underlay consists of a substrate and unsymmetrical double-split ring structural units which are periodically arranged on the substrate to form a two-dimensional array on the substrate. The unsymmetrical double-splitring structural unit is a metal split ring formed by two metal arcs with different lengths. The underlay of the invention has simple structure, large electromagnetic enhanced effect, good stability and reproducibility. Two strong extinction peaks in a near infrared region and an optical frequency, respectively correspond to a first-order resonance (I) and a second-order resonance (II); the electric filed enhanced effect can be further improved by reducing the width of the slit and optimizing a top structure; the wavelength range of the first phase resonance (I) and the second phase resonance(II) can be adjusted through structure parameters, so that the wavelength range of the surface-enhanced optical spectrum application can be satisfied.

The invention discloses a high-stability multi-wavelength optical fiber laser with adjustable wavelength intervals, and belongs to the field of optical fiber communication and instruments and meters.According to the laser, a polarization controller II (09), a polarization maintaining optical fiber I (10), a polarization controller III (11) and a polarization maintaining optical fiber II (12) aresequentially connected between an interface 081 and an interface 082 of an optical fiber coupler I (08) to form a double-order Sagnac filter. A pump (01),a wavelength division multiplexer (02), an erbium-doped optical fiber (03), a first optical fiber coupler (04), a high-nonlinearity optical fiber (05), a first polarization controller (06) and a second optical fiber coupler (07) jointly form an NALM-NOLM structure, mode competition is inhibited, and the laser output stability is greatly improved. The wavelength interval can be changed by adjusting two polarization controllers in the filter. The laser has the advantages of simple structure, flexible output wavelength and the like, and is suitable for a wavelength division multiplexing system.

The invention discloses a four-wave mixing based continuously trap wave tunable microwave photonic notch filter. Multi-wavelength laser is generated by four-waving mixing to serve as a light source of the microwave photonic filter to realize a multi-tapping effect. Sidebands and phases of photoelectric current generated after phase modulation control by a waveshaper form trap waves, and phase shift magnitude is introduced additionally to form a complex coefficient to realize continuous tuning of the trap waves. Passband center frequency of output radio-frequency signals of the microwave photonic filter has characteristics of tunable band-reject filter waves, and tunability in trap wave center frequency of the filter is realized according to the phase shift magnitude introduced to optical carriers and modulating signals by the waveshaper. The microwave photonic notch filter has advantages of simple structure, developed operation techniques and low cost, solves problems of small tuning range and failure in continuous tunability of existing phase modulation based microwave photonic notch filters and is applicable to fields of national defense, industrial production and civilian use.

The invention discloses a multi-wavelength external cavity laser for a non-fluorescence raman spectrometer. More than two laser diodes with equal central wavelengths in an array are driven to be independently opened and closed through a power supply switching circuit; output light beams are calibrated into parallel collimated laser beams through a collimating laser calibration optical element; a special design is adopted by a grating; different grating periods are set for incident point regions, corresponding to the collimated laser beams, of the grating; the collimated laser beams form zero-order reflected beams and first-order diffracted beams after being diffracted by the grating; the zero-order reflected beams are output in the same direction and have a wavelength difference; the first-order diffracted beams return to the inside of the corresponding laser diodes along the original path to participate in internal mode competition of a resonant cavity; and the zero-order reflected beams are converged into an optical fiber combiner through an optical fiber coupling lens for wavelength output. The wavelength output is switched by the circuit, so that the unreliability and the possible error of conventional mechanical adjustment are eliminated; a tuning structure is relatively simple and stable; high stability of output wavelengths is ensured; the wavelength output repeatability in actual operation is high; and the tuning accuracy is relatively high.

The invention provides a broadband microwave photon phase coded signal generation device and method. An output port of a laser is connected with an input port of a carrier modulation module, an outputport of the carrier modulation module is connected with an input port of a phase encoding modulation module, an output port of the phase encoding modulation module is connected with an optical inputport of a photoelectric detector after passing through the optical fiber, and the photoelectric detector outputs a required phase encoding signal. According to the invention, an integrated polarization multiplexing modulator is used to generate an optical carrier signal, and then the polarization modulator is used to carry out phase coding modulation on the generated carrier signal so as to generate a phase coding signal without baseband interference. The amplitude of the signal is tuned by controlling the DC bias voltage of the polarization multiplexing modulator, so the system provided by the invention is expanded to a phased array radar system and a frequency-controlled array radar system, has a wider application scene, and is of great significance to the fusion and development of next-generation military and civil radar systems.

The invention relates to a reconstructible high-frequency chirped pulse signal generating device and method, and mainly aims at solving the problems that high-frequency chirped pulses generated in a present method cannot satisfy high frequency and high-precision range finding requirements for a modern radar. A femto second pulse signal generated by a femto second laser (1) is input to a fiber loop including a linear chirp fiber Bragg grating (7) and an adjustable delay line (6) via a three-port circulator a (2) for spectrum shaping, the optical pulse signal after spectrum shaping is input to a reconstructible chirp Bragg grating (9) via a three-end circulator b (3) for frequency-time mapping, an optical high-frequency chirped pulse signal, and a photoelectric detector (4) converts the optical high-frequency chirped pulse signal into an electrical high-frequency chirped pulse signal. Reconstructible frequency-time mapping is realized, the reconstructible high-frequency chirped pulse signal is realized, and the requirement of high bandwidth can be satisfied at the same time.

The invention discloses a phase shift keying demodulator and a four-phase phase shift keying demodulator, wherein the phase shift keying demodulator comprises a beam splitter and a reflector, the beam splitter and the reflector are fixed on the same flat plate; and the phase shift keying demodulator further comprises a phase delay device, wherein the phase delay device is arranged on the flat plate and located on an optical path between the beam splitter and the reflector, and the phase delay device is used for generating phase delay for one path of light split by the beam splitter. With the phase shift keying demodulator and the four-phase phase shift keying demodulator, two beams of optical signals can be controlled or tuned accurately; and the phase shift keying demodulator and the four-phase phase shift keying demodulator both are simple in structure and reliable in performance.