41results about How to "Reduce half wave voltage" patented technology

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 provides a user terminal in a quantum key distribution system. The quantum key distribution system comprises a modulation light source, and the modulation light source comprises a phase preparation laser, an optical fiber circulator and a pulse production laser. The invention further provides a MDI-QKD system, which comprises a user terminal and a public measure terminal, wherein the user terminal comprises an Alice terminal and a Bob terminal; the public measurement terminal is a Charlie terminal; each of the Alice terminal and the Bob terminal comprises the modulation light source. The invention further provides a key distribution method of the MDI-QKD system based on light injection, and a networked MDI-QKD system. The user terminal provided by the invention simplifies a structure of each of a phase modulation laser and the pulse production laser, and is unnecessary to set a phase feedback system. The MDI-QKD system provided by the invention realizes the integrated structure of the light source, the phase modulator and an intensity modulator; the limitation to the system high-speed application by the phase modulator and the intensity modulator are relieved; the modulation light source can directly generate light pulse with pure phase difference information, and the consistency control on multiuser light pulse phase standards can be realized.

The invention discloses an all-fiber electro-optical modulator based on graphene materials and a method of the all-fiber electro-optical modulator. The all-fiber electro-optical modulator based on the graphene materials comprises a single mode fiber, a silicon dioxide groove-type substrate, an Al2O3 transition thin layer and a graphene membrane, wherein the single mode fiber is arranged on the silicon dioxide groove-type substrate and fixed through sealed epoxy glue, a groove is formed in the single mode fiber, the Al2O3 transition thin layer is arranged in the groove, and the graphene membrane is arranged on the Al2O3 transition thin layer. Conductivity performance of graphene is changed through change of voltage applied on a metal electrode, therefore an imaginary part or a real part of an effective refractive index of a graphene composite layer structure is changed, and an electric absorption strength modulator or a phase modulator is achieved. The all-fiber electro-optical modulator based on the graphene materials and the method of the all-fiber electro-optical modulator can achieve design of the all-fiber electro-optical modulator, and have the advantages of being tiny in size, little in power consumption, low in insertion loss, high in modulating speed, beneficial for optical integration and the like. In addition, due to the fact that additional optoelectronic devices are not introduced, the all-fiber electro-optical modulator based on the graphene materials and the method of the all-fiber electro-optical modulator are suitable for being used in an all-fiber communication system and a dense wavelength division multiplexing (DWDM) system.

The present invention discloses a high-speed modulator which comprises an optical waveguide structure and a traveling wave electrode structure, the optical waveguide structure comprises a first optical waveguide arm and a second optical waveguide arm, a traveling wave electrode comprises a grounding electrode and a signal line, and the signal line applies electric fields or voltages in opposite directions to the first optical waveguide arm and the second optical waveguide arm. The first optical waveguide arm and the second optical waveguide arm are both of a folding structure, and the signal line is folded along with the first optical waveguide arm and the second optical waveguide arm, so that an electric field or voltage applied to the first optical waveguide arm and the second optical waveguide arm is kept unchanged. Or the electric field or the voltage applied to the first optical waveguide arm and the second optical waveguide arm is synchronously changed. Compared with the prior art, the device has the advantages that the folding structure of the optical waveguide is matched with the ground-signal-ground coplanar waveguide traveling wave electrode structure, modulation addition of light in different sections of the waveguide is achieved, the longer phase shift waveguide length can be achieved within the limited device length, and meanwhile it can be ensured that the bandwidth meets the application requirement.

The invention relates to an all solid-state 455nm pulsed laser based on a neodymium-doped fluorinated lutetium lithium crystal, which is suitable for underwater laser communications. The all solid-state 455 nm pulsed laser is characterized by comprising a laser diode output with tail fibers, and a pump optical coupling system, a laser cavity and a multiple frequency crystal are sequentially arranged along the advanced direction of the laser diode outputting a laser, wherein the laser cavity comprises an Nd: LiLuF crystal and an electrooptic Q-crystal. The invention has the characteristics of compact structure, small size, long life and stable working.

The invention discloses a lithium niobate film electro-optical modulator with the high modulation efficiency. Electrodes of the lithium niobate film electro-optical modulator are prepared into a vertical-type structure, the upper layer electrodes (the signal electrodes) are located above optical waveguides, the lower layer electrodes are ground electrodes, the vertical type electrode structure canachieve the 100% modulation efficiency for the optical waveguides, and the modulation efficiency is much higher than the 40-50% electro-optical modulation efficiency of a traditional lithium niobateelectro-optical modulator; in addition, the lithium niobate film material with the single-crystal structure, the thickness being 0.1-10 micrometers is adopted, and the shorter electrode interval is obtained compared with the traditional lithium niobate electro-optical modulator. Due to the two factors, the half-wave voltage of the lithium niobate electro-optical modulator can be greatly lowered.

The invention discloses a loading strip-structure silicon / PLZT hybrid waveguide-based Mach-Zehnder electro-optical modulator. The silicon / PLZT hybrid waveguide-based Mach-Zehnder electro-optical modulator comprises a waveguide, an MMI-based Mach-Zehnder interference structure and a coplanar waveguide electrode structure, wherein the waveguide comprises a silicon core layer, a ferroelectric thin film lower coating layer and a silicon dioxide upper coating layer, and the coplanar waveguide electrode structure is designed in order to achieve high-speed electro-optical modulation. The modulator sequentially comprises a coplanar waveguide electrode, the silicon dioxide upper coating layer, a silicon waveguide layer, a PLZT lower coating layer and an NST substrate from top to bottom, wherein thecoplanar electrode can be used for loading a radio frequency signal and loading the radio frequency signal to an optical wave to achieve electro-optical modulation. By the silicon / PLZT hybrid waveguide-based Mach-Zehnder electro-optical modulator, high modulation depth, low transmission loss and high modulation bandwidth can be achieved, and the silicon / PLZT hybrid waveguide-based Mach-Zehnder electro-optical modulator can be applied to an integrated high-speed microwave optical network.

The invention relates to a Z-tangent LNOI electro-optical modulator capable of improving modulation efficiency and an application thereof. The Z-tangent LNOI electro-optical modulator comprises a substrate, an insulating layer, a waveguide core layer, an upper cladding layer, a signal electrode and a ground electrode, wherein a bottom of the substrate is provided with a groove; the insulating layer is disposed on the substrate; the waveguide core layer is arranged on the insulating layer, and a tangential direction of the waveguide core layer is Z-tangent; the upper cladding layer is arrangedon the waveguide core layer, is used for forming a refractive index difference with the waveguide core layer so as to limit transmission of an optical field, and is used as a support structure of an upper-layer electrode; the signal electrode is arranged at the position, corresponding to an optical waveguide, of the cladding layer and used for applying an electric signal to form an electric fieldto perform electro-optical modulation on light in the waveguide core layer; and the ground electrode is arranged in the groove, and an electric field between the ground electrode and the signal electrode is along an optical axis direction of the Z-tangent LN. In the invention, ultra-efficient electro-optical modulation of near 100% of the electric field to an optical field is realized so that a half-wave voltage of the modulator is greatly reduced, and power consumption of the modulator is reduced.

The invention discloses a lithium niobate film electro-optical modulator chip. A Y-branch waveguide, a waveguide optical path of a radio frequency modulation part and a waveguide optical path of a bias voltage control part are separated in space, and a 90-degree bent waveguide is used for connecting the waveguide optical paths, so that the length of the lithium niobate film electro-optical modulator chip can be remarkably shortened; in addition, the invention also provides a lithium niobate film electro-optical modulator, optical fibers serving as an optical input port and an optical output port are placed on the same side of a lithium niobate film electro-optical modulator chip, and the optical fiber port protection structure of the electro-optical modulator is placed on the same side of the device. The total length of the lithium niobate film electro-optical modulator can be effectively shortened.

An electro-optic modulation device provided by the present invention includes a semiconductor laser, a collimator, a polarizer, a driving source module, an electro-optic modulation crystal, and a polarizer. This device is mainly aimed at the 800nm ​​band, the modulation rate is 100Mbps to 500Mbps, and the maximum optical power output is greater than 0.5w. The semiconductor laser is connected to the collimator through an optical fiber. The laser light passing through the collimator becomes polarized light after passing through the polarizer. The polarized light is modulated after passing through the electro-optic modulation crystal. Use the unit. The external signal source and the driving source module are connected with a high-frequency coaxial cable, the external signal source provides a high-frequency, high-power square wave AC signal for the driving source module, and the electro-optical modulation crystal and the driving source module are connected by a high-frequency coaxial The cable is connected, the output signal of the driving source module is sent to the electro-optic modulation crystal through the high-frequency coaxial cable and the traveling wave electrode, and the optical feedback signal of the electro-optic modulation crystal realizes the real-time control of the static working point.

The invention provides a reflection-type electro-optic phase modulator. The reflection-type electro-optic phase modulator comprises an electro-optic crystal, optical waveguide and modulation electrodes; the optical waveguide comprises n first light paths and n+1 second light paths, wherein n is greater than or equal to 2; the first light paths are sequentially arranged between a light-in surface and a light-out surface of the electro-optic crystal; the second light paths are connected between the light-out end of the ith first light path and the light-in end of the i+1 first light path, wherein i is equal to 1, 2, ..., n; high-reflection films are arranged at the connecting positions of the first light paths and the second light paths; the modulation electrodes are arranged on the two sides of the first light paths and the second light paths respectively. Compared with the prior art, according to the reflection-type electro-optic phase modulator, multiple Z-shaped light paths are adopted to form the optical waveguide, the action length of the electro-optic phase can be increased under the condition of not increasing the length of the electro-optic phase modulator, and half-wave voltage is lowered. Meanwhile, the structural size of the electro-optic phase modulator can be reduced, integration is easy, and the practicability of the electro-optic phase modulator is improved.

The invention discloses an electro-optical switch with low half-wave voltage, which comprises an insulating shell (201) and an electro-optic crystal (202); a pair of lateral surfaces of the crystal is plated with a metal conducting layer (203) respectively; an indium foil (204) is attached to the outside of the metal conducting layer; an inner metal electrode (205) is attached to the outside of the indium foil; and an external metal electrode hole (206) is reserved on the outside of the inner meal electrode. Through the electrode design, under the condition that the crystal has a certain length, when the electro-optical switch works, the ignition on the light-transmitting surface of the crystal caused by too close distance between the electrodes can be avoided so as not to influence the use of the switch or damage the light-transmitting surface of the crystal. The design effectively reduces the half-wave voltage of the electro-optical switch, prolongs the service life thereof and lowers the rigorous requirement on a switch driving power supply.

The invention provides an integrated light emitting device, which comprises a laser device, an optical frequency comb, a wavelength decomposition demultiplexer and a wavelength division multiplexer which are arranged in sequence in the propagation direction of light, wherein the laser device is used for generating a single-wavelength light source signal; the optical frequency comb is used for receiving the single-wavelength light source signal and processing the signal into a plurality of optical carrier signals with equal wavelength intervals; the wavelength decomposition demultiplexer is used for receiving the multi-wavelength optical carrier signals and decomposing the optical carrier signals into multiple paths of sub-optical carrier signals; and the wavelength division multiplexer isused for combining the multiple paths of sub-optical carrier signals into one path of optical signal and outputting the optical signal. According to the integrated light emitting device, the light source signal is emitted from one laser device, the optical frequency comb receives the light source signal and generates the plurality of carrier signals with equal wavelength intervals to output the light carriers, the problems of high power consumption and difficult temperature control circuit design caused by excessive light emitters are solved, and the production cost of the light emitting device is reduced.

The invention provides a flexible lithium niobate film electroencephalogram detection chip and a device thereof, and the chip comprises a flexible lithium niobate substrate which is provided with an optical waveguide and a coplanar traveling wave electrode; a flexible support layer used for providing support for the flexible lithium niobate substrate; and an electrode arranged on the surface of the flexible supporting layer, and wherein the coplanar traveling wave electrode is electrically connected with the electrode. According to the invention, the flexible lithium niobate substrate and the flexible supporting layer have flexibility and can be better attached to the surface of the human brain; the flexible supporting layer is attached to the surface of the human brain, the electrodes of the flexible supporting layer make electrical contact with the human brain, the electrodes collect electroencephalogram signals and transmit the electroencephalogram signals to the coplanar traveling wave electrodes on the lithium niobate substrate, a weak electric field is formed between the coplanar traveling wave electrodes, the refractive index of the flexible lithium niobate substrate is changed, light is transmitted from the optical waveguide and passes through the modulation area with the changed refractive index, the optical path is changed, and the phase is changed during output. and long-distance transmission is light transmission, so that the long-distance transmission is not easily interfered by electromagnetic interference.

The invention relates to the technical field of microwave photon signal generation, in particular to a high-quality time domain mode-locked optoelectronic oscillator system and method based on the Brillouin effect. A laser outputs an optical signal to a phase modulator, an optical isolator protection device is arranged, and the signal is output to an optical circulator; the optical circulator receives a signal input by the pump laser and outputs the signal to the optical attenuator, and the optical attenuator reduces signal energy and sends the signal energy to the photoelectric detector; the photoelectric detector converts an optical signal into a microwave signal, the loss is compensated by the electric amplifier, and the microwave signal is sent to the first electric coupler; after the first electric coupler receives signals, one path of signals is transmitted to the electric spectrum analyzer and the digital storage oscilloscope to be stored, and the other path of signals is sent to the second electric coupler, receives external radio frequency signals and inputs the signals to the phase modulator to close a loop. Conversion from phase modulation to intensity modulation is realized, an optical filter structure in the system is simplified, time domain mode locking operation is introduced, and a broadband frequency comb microwave signal can be adjusted.

The invention discloses a high-performance straight-waveguide-type electro-optic phase modulator and a preparation method thereof. The electro-optic phase modulator has a plate-capacitor-type structure, and comprises a single crystal which is equivalent to a dielectric layer and electrode layers on the upper and lower surfaces of the single crystal. The single crystal is a binary (1-x)Pb(Mg1 / 3Nb2 / 3)O3-xPbTiO3 system or a ternary (1-x-y)Pb(In1 / 2Nb1 / 2)O3-xPb(Mg1 / 3Nb2 / 3)O3-yPbTiO3 system. The straight-waveguide-type electro-optic phase modulator is capable of using the domain steering and the difference of birefringence of a ferroelectric, inducing the domain steering through a prefabricated electric field applied to coplanar electrodes, producing the change of the refractive index which is up to 3% in the local section, and effectively constructing a simple optical waveguide structure which is easily processed and manufactured. The high-performance straight-waveguide-type electro-optic phase modulator has the characteristics of very low half-wave voltage, low insertion loss, high bandwidth and excellent phase modulation ability. The ferroelectricity and the strong optical nonlinearity are combined, various optical information conversion devices can be designed, and the effective control of the photon polarization state, the detection of a weak signal and the generation and control of a phased array signal are realized. The high-performance straight-waveguide-type electro-optic phase modulator is suitable for the quantum secret communication technology and microwave photonics radar technology fields.

The invention discloses an auto-collimation spatial lithium niobate electro-optic phase modulator and a preparation method thereof. The auto-collimation spatial lithium niobate electro-optic phase modulator comprises an electrode (1), magnesium-doped lithium niobate crystal near-surface refractive index gradient layers (2) and a high-refractive-index magnesium-doped lithium niobate crystal core layer (3), wherein the high-refractive-index magnesium-doped lithium niobate crystal core layer (3) is arranged between two poles of the electrode (1); the magnesium-doped lithium niobate crystal near-surface refractive index gradient layers (2) are arranged in a space formed by the high-refractive index magnesium-doped lithium niobate crystal core layer (3) and the electrode (1) in pairs. Compared with an existing lithium niobate space type electro-optic phase modulator, the lithium niobate space type electro-optic phase modulator has lower half-wave voltage, higher light intensity bearing capacity, lower transmission loss and higher modulation efficiency; the input light beam does not need to be collimated, the complexity of the system is reduced, the device can be directly connected with a large-core-diameter and large-mode-field optical fiber, and the application scene is expanded.

The invention discloses a method of making an optical planar waveguide. According to the invention, the cold welding process is used for bonding a laser crystal waveguide strip and an electro-optical crystal waveguide strip, excellent heat dissipation of a device at work can be achieved through accurate pressure control and selection of appropriate bonding material and substrate material, and internal stress accumulation due to uneven pressure can be eliminated. The making method is mature and high in consistency and can be batched.

The invention provides a reflection-type spatial electro-optical modulator based on graphene, and relates to electro-optical modulators. A spatial optical coupling module and a waveguide type electro-optical modulation module are arranged; the spatial optical coupling module is provided with an optical transparent prism, and the waveguide type electro-optical modulation module is provided with a dielectric upper cladding layer, a metal upper external electrode, a graphene upper electrode, an electro-optical dielectric core layer, a metal lower external electrode, a graphene lower electrode anda dielectric lower substrate. When the waveguide type electro-optical modulation module works under the driving of external voltage, modulation of spatial light waves can be achieved. A full-dielectric optical waveguide is used, so that the quality factor of the modulator is high compared with a traditional spatial electro-optical modulator, the resonance line width is small, and it is hopeful toobtain small half-wave voltage; compared with the traditional spatial electro-optical modulator based on surface plasmon resonance, the modulator can act on transverse electric waves or transverse magnetic waves and has no polarization dependence.

The invention provides a transverse modulation KDP type electro-optic Q switch which is characterized in that two identical KDP type crystals are combined, the KDP type crystals are cut into differenttypes, x and z represent crystal axes of the KDP type crystals, l and b represent the length direction and the width direction of the cut crystals respectively, the value range of the angle theta isshown in the specification, and the value range of the angle theta is shown in the specification; the length direction of the KDP type crystal is a light transmission direction, and the thickness direction of the KDP type crystal is an electric field applying direction. The switch is advantaged in that the half-wave voltage of the electro-optic Q switch is adjustable, the switch shape and the electrodes are easy to prepare, and the electric field is more uniform, so the extinction ratio is higher, the influence of natural birefringence and temperature on the electro-optic Q switch is smaller,requirements on length deviation, temperature deviation and the like of two crystals for matching are lower, the allowable range is larger, and the electro-optic Q switch is more practical.

The invention relates to a high-frequency electro-optic position phase modulator which structurally comprises a waveguide coaxial converter, a first waveguide, a bolt, a light through hole, an E-surface bent waveguide, a second waveguide, a first stopping waveguide, an electro-optic crystal and a second stopping waveguide. The high-frequency electro-optic position phase modulator can be used for restraining a stimulated brillouin effect of a laser system and uniformly and smoothly forming dispersion of a spectral angle of a high-power laser device; the high-frequency electro-optic position phase modulator has the characteristics that the microwave and optical wave phase velocities are matched, the modulating efficiency is high and the light caliber is large; and the high-frequency electro-optic position phase modulator is suitable for the microwave operating frequency range of 2-20GHz.

The invention belongs to the technical field of phoelectron, and particularly relates to an acousto-optic and electrooptical device with polarization maintaining optical fibers. The acousto-optic andelectrooptical device with polarization maintaining optical fibers comprise inputting polarization maintaining optical fibers, a shell and outputting polarization maintaining optical fibers, an inputting end collimator, a polarizer, an electrooptical modulator, a polarization analyzer, an acousto-optic modulator and an outputting end collimator which are successively connected are arranged in theshell; the inputting polarization maintaining optical fibers and the outputting polarization maintaining optical fibers are mounted on the outer surface of the shell; and a signal socket which is fixed on the outer surface of the shell is connected with the electrooptical modulator, a radiofrequency socket and the acousto-optic modulator through leads. The electrooptical modulator is combined to the acousto-optic modulator, high-speed modulation is realized by a modulation function of the electrooptical modulator, and high on-off extinction ratio is realized by the acousto-optic modulator.

The invention discloses a poling method for a relaxor ferroelectric single crystal as a nonlinear optical material. The method comprises an annealing process and a polarization process; the relaxor ferroelectric single crystal comprises a binary (1-x)Pb(Mg1 / 3Nb2 / 3)O(3-x)PbTiO3 system and a ternary (1-x-y)Pb(In1 / 2Nb1 / 2)O(3-x)Pb(Mg1 / 3Nb2 / 3)O(3-y)PbTiO3 system; according to the annealing process, the relaxor ferroelectric single crystal after grinding and polishing is subjected to annealing treatment in atmosphere, stress caused by machining is removed, and spontaneous strain produced in a ferroelectric phase forming process is released to the great degree through quite slow cooling, so that the probability of cracking caused by electrically induced domain rotation in the crystal poling process is reduced. Besides, after an electric field is removed, a remaining depolarization field can be induced to form a nanometer domain structure. In order to guarantee formation and stability of a single-domain structure, the remaining depolarization field can be compensated by bulk shielding effect formed through electrode injection, the relaxor ferroelectric single crystal with high poling performance and stable performance is obtained, and the material has the characteristics of small half-wave voltage, large photo damage threshold, large electro-optic coefficient and the like and is far better than BBO, KTP, LN and other materials.

The invention discloses a quantum key distribution system based on a reference frame-independent protocol, which uses light injection semiconductor lasers to generate quantum states with encoded information, replacing the traditional scheme of light sources and quantum state encoding modules. The photon time and phase difference information is generated by the light injection semiconductor laser in the quantum key encoding end, the first laser driver, the second laser driver, the pulse generation laser, the phase preparation laser, the first three ports in the quantum key encoding end The circulator forms the light injection semiconductor laser, and the second laser driver controls the phase preparation laser to inject the phase-modulated optical pulse with the pre-adjusted Δφ phase into the pulse generation laser, so that the pulse generation laser controlled by the first laser driver can generate a pair of phase difference Δφ Double-pulse signal light, thereby generating a pulse sequence with time and phase encoding information. The technical solution improves the anti-interference and coding rate of the system, and is beneficial to product integration and miniaturization.

An electro-optical intensity modulator and its application to realize the improvement of the switch extinction ratio, the electro-optic intensity modulator includes an input optical waveguide; a first coupler; a first pair of phase modulation arms, and the sides of the two arms are provided with a first pair of rows Wave electrode; multi-mode interference structure, which includes two input optical waveguides, a multi-mode interference region and two output optical waveguides, used to convert the two beams of light modulated by the first pair of phase modulation arms through the multi-mode interference region The new two beams of light that are output; the second pair of phase modulation arms, the sides of the two arms are provided with a second pair of traveling wave electrodes; the second coupler and the output optical waveguide, which are used to combine the second coupler after the light output. The structure of the present invention can compensate the decrease of the extinction ratio caused by the asymmetry caused by the process error by tuning the optical power ratio of the two branches at the input end of the modulator, significantly improve the extinction ratio, increase the process tolerance, and improve the production efficiency and good quality Rate.

The invention discloses a push-pull photonic crystal zipper cavity optical accelerometer with electromagnetic feedback. Light of a narrow linewidth light source is coupled through a spot size converter and enters a Y waveguide to realize light splitting, and light of a first branch end passes through a first input straight waveguide, a first upper nanometer micro beam and a first output straight waveguide and then is received by a first photoelectric detector. The light of the second branch end passes through a second input straight waveguide, a second lower nanometer micro beam and a second output straight waveguide and then is received by a second electric detector. The left driving electrode, the spring oscillator structure and the right driving electrode are respectively arranged between the first input straight waveguide and the second input straight waveguide, between the first upper nanometer micro-beam and the second lower nanometer micro-beam, and between the first output straight waveguide and the second output straight waveguide; the left driving electrode and the right driving electrode are electrically connected with the spring oscillator structure; and a permanent magnet is embedded in the ceramic base below the spring oscillator structure. According to the invention, high-resolution and large-bandwidth detection is realized, common-mode interference noise is suppressed, and the advantages of high integration level, large adjustable range and electromagnetic interference resistance are realized.