47 results about "Multimode interference" patented technology

The application relates to the technical field of lasers, in particular to a semiconductor laser for a quantum gyroscope and a preparation method thereof. The semiconductor laser for the quantum gyroscope comprises a stacking structure, the stacking structure comprises an N-type substrate, an N-type cladding layer, an N-type waveguide layer, an active region, a first P-type waveguide layer and a waveguide structure which are stacked in a first direction in sequence, and the waveguide structure comprises a low-duty-cycle V-shaped groove grating, a multimode interference coupling beam splitting waveguide, a gain waveguide array, a multimode interference coupling beam combining waveguide, a high-duty-cycle V-shaped groove grating and a micro-tapered waveguide which are arranged and connected in a second direction in sequence. The application is favorable for realizing the semiconductor laser for the quantum gyroscope with high power and narrow linewidth under the premise of reducing the complexity of the device structure.

The invention discloses a lithium niobate eight-channel beam splitter capable of being used for an optical phased array. The lithium niobate eight-channel beam splitter comprises a silicon substrate, a silicon dioxide buffer layer, a lithium niobate core layer and a silicon dioxide cladding, the silicon dioxide buffer layer is attached to the silicon substrate, and the lithium niobate core layer is arranged on the silicon dioxide buffer layer; the silicon dioxide cladding is attached to the lithium niobate core layer and wraps the lithium niobate core layer; the lithium niobate core layer comprises an input section, a multi-mode interference coupling section and an output section which are connected in sequence, and the wide end of the input conical waveguide section is connected with one side of the multi-mode interference coupling section; and the wide ends of the eight output conical waveguide sections are connected with the other side of the multimode interference coupling section. The beam splitter is manufactured based on lithium niobate, is small in size, compact in structure, simple to process, large in manufacturing tolerance and high in product yield, and can realize uniform beam splitting in a working wave band.

This application provides a resonant modulator applicable to the field of optoelectronic information technology. The resonant modulator includes a substrate layer, a buried layer, a core layer, and an upper cladding layer. The core layer includes a multimode interference coupler and a connecting waveguide. The multimode interference coupler includes a multimode interference region and a main input port waveguide, a main output port waveguide, a feedback output port waveguide, and a feedback input port waveguide. The two ends of the connecting waveguide are optically connected to the feedback output port waveguide and the feedback input port waveguide, forming an optical feedback loop with the multimode interference coupler. An electro-optic modulation unit is associated with a first region of the connecting waveguide and is used to adjust the effective refractive index of the connecting waveguide by applying an electrical signal to change the resonant state of the resonant modulator. Based on the above structure, the sensitivity to coupling spacing and manufacturing errors can be reduced, and the device operating tolerance and modulation stability can be improved. This application also provides an optical computing system and a photonic integrated system.

The invention relates to the technical field of multimode interference, and provides a central wavelength tunable multimode interference device which comprises an input waveguide region, a multimode interference region and an output waveguide region which are connected in sequence, the multimode interference region comprises a core layer, the core layer is made of a high-refractive-index material, and the output waveguide region is made of a high-refractive-index material. And a modulation electrode structure for modulating the refractive index of the core layer is arranged on the multimode interference region. The invention further provides a manufacturing method of the multimode interference device with the tunable central wavelength and a coherent modulator. Refractive index modulation is carried out on the core layer of the multi-mode interference area through the modulation electrode structure, in the multi-mode interference area, the effective refractive index directly determines the self-mapping point positions of different wavelengths, therefore, the effect of tunable central wavelength can be achieved through refractive index modulation, and through selection of different bias voltages, the tunable wavelength of the multi-mode interference area can be achieved. And the output effect of the optical power in the output waveguide is tuned.

The application relates to the technical field of optical fiber sensing, and discloses a miniaturized interrogator and a distributed optical fiber sensing system, which comprise a laser chip and an interrogator chip; the interrogator chip comprises a first optical port, a second optical port, a third optical port, a fourth optical port, a first polarization filter, a second polarization filter module, a selection switch, a beam splitter, a modulator, a polarization rotation beam splitter, a 1*2 multimode interference coupler, a first 2*4 multimode interference coupler, a second 2*4 multimode interference coupler, a first balanced detector, a second balanced detector, a third balanced detector and a fourth balanced detector. The integrated degree can be effectively improved, the system cost, volume and weight are reduced, the complex device coupling process is avoided, the production efficiency and consistency are improved, and the sensing performance is kept high.

The invention provides an optical mixer based on metasurface integration and a preparation method thereof, and belongs to the field of mixers. The mixer comprises a circularly polarized light beam splitter which comprises a first substrate, a liquid crystal structure, a second substrate and a nanorod array which are stacked in sequence; the nanorod array is used for separating the signal light and the local oscillation light into signal light left-handed rotation light, signal light right-handed rotation light, local oscillation light left-handed rotation light and local oscillation light right-handed rotation light; the liquid crystal structure is used for regulating and controlling the initial phases of the output left-handed light and right-handed light; the first multimode interference coupler is used for receiving and mixing the signal light left-rotation light output by the circularly polarized light beam splitter with the local oscillation light left-rotation light to obtain four paths of left-rotation polarized light components with different phases; and the second multimode interference coupler is used for receiving and mixing the right-handed light of the signal light output by the circularly polarized light beam splitter with the right-handed light of the local oscillation light to obtain four paths of right-handed polarized light components with different phases.

The invention discloses an optical switch device and a complex-valued optical neural network system, and belongs to the technical field of optical computing. The optical switch device is a two-input two-output device and comprises first to sixth waveguides, and first and second multimode interference couplers. Phase shifters are attached to the third waveguide and the fifth waveguide and / or the fourth waveguide and the sixth waveguide to form a group of configuration units which are used for loading real part and imaginary part data of a complex number. The phase shifter comprises a nonvolatile phase change material layer and a heating layer which are sequentially arranged from bottom to top, is used for realizing the function of the phase shifter, greatly reduces the static power consumption, improves the energy efficiency, is suitable for realizing the complex value optical neural network, and is also beneficial to large-scale integration. The complex-valued optical neural network system constructed based on the optical switch integrates input, calculation, reference and coherent detection modules, can synchronously complete amplitude and phase detection of optical signals, effectively supports complex-valued optical calculation, and has the advantages of low power consumption and high integration level.

Structures for a power splitter that include a multimode interference coupler and methods of forming such structures. The structure comprises a multimode interference coupler including a grating having a plurality of grating lines, an input waveguide core, and an output waveguide core. The grating lines are disposed between the input waveguide core and the output waveguide core. The structure further comprises a resistive heating element adjacent to the grating lines.

The application discloses a graphene-coated surface saturable absorber device of a multimode optical fiber with an internal microstructure, which adopts a mixed structure of graphene and a graded-index multimode optical fiber. The saturable absorber device comprises a first single-mode optical fiber, a mixed structure based on a multimode optical fiber, and a second single-mode optical fiber. The mixed structure based on the multimode optical fiber is composed of a tapered graded-index multimode optical fiber with an internal microstructure and a single-layer graphene film. The graded-index multimode optical fiber is first subjected to a micro-tapering treatment, then a microstructure is inscribed in the core inside the taper waist, then the graphene film is coated on the surface of the taper waist of the optical fiber, and finally the single-mode optical fibers are fused at both ends of the multimode optical fiber. The saturable absorber combines the nonlinear multimode interference effect in the multimode optical fiber and the saturable absorption characteristics of graphene, can perform secondary compression on the pulse width of a high-energy pulse, and thus obtains an ultrashort pulse. The application has the advantages of a solid structure, strong stability, a high damage threshold and the like, and provides an effective technical means for obtaining a stable ultrashort pulse mode locking.

The invention discloses a compact asymmetric multimode interference coupler hybrid reverse design method based on pixelated topological optimization, and belongs to the technical field of integrated photonic device design. The invention aims to solve the problems of difficulty in realizing any splitting ratio under a compact size, long design time and low efficiency in the design of the conventional asymmetric multimode interference coupler. According to the method, for a multimode interference coupler, a discrete model is established, and a corresponding two-dimensional binary matrix is used as an individual chromosome code; a fitness function of an individual is constructed through the port transmissivity obtained through three-dimensional finite difference time domain simulation calculation, and a genetic algorithm is adopted for optimization; after each generation of evolution is finished and a current global optimal individual is locked, a round of local search refining is carried out; and then traversing the topological structure based on the global optimal topological structure, determining boundary pixels of which the refractive indexes are suddenly changed according to the logical value difference between pixel points and neighborhood pixels thereof, generating a boundary pixel set, and performing boundary refinement.

The utility model discloses an anti-crosstalk multimode interference coupler for an MZI (Mach Zehnder Interference) structure. The coupler specifically comprises a single-mode input waveguide, a multimode interference area waveguide, two single-mode output waveguides, two stray light output waveguides, two stray light interference area waveguides and two metal absorption areas, the metal absorption region, the stray light interference region, the stray light output waveguide, the multi-mode interference region waveguide and the single-mode output waveguide are connected in sequence, and the coupler is symmetric about the single-mode input waveguide.

The present application relates to the technical field of optical device design, and particularly relates to a VCSEL resonant cavity parameter prediction method and system for multimode suppression. The method comprises the following steps: obtaining surface relief microstructure data of a VCSEL resonant cavity, and performing adaptive spatial discretization according to the surface relief microstructure data to obtain relief grid data; performing mixed boundary condition setting according to the relief grid data to obtain mixed boundary data; performing in-cavity simulation according to the relief grid data and the mixed boundary data to obtain in-cavity simulation data; performing multimode interference analysis on the in-cavity simulation data to obtain multimode interference data; performing quantitative coupling according to the surface relief microstructure data and the multimode interference data to obtain a relief coupling prediction model; obtaining experimental simulation data, and performing optimization iteration according to the relief coupling prediction model and the experimental simulation data to obtain a relief cavity parameter prediction model. The present application realizes simulation of in-cavity mode distribution and multimode interference, and improves single-mode output stability.

The invention relates to the technical field of lasers, in particular to a semiconductor laser facing a quantum gyroscope and a preparation method thereof.The semiconductor laser facing the quantum gyroscope comprises a stacked structure, and the stacked structure comprises an N-type substrate, an N-type cladding, an N-type waveguide layer, an active region, a first P-type waveguide layer and a waveguide structure which are sequentially stacked in the first direction, the waveguide structure comprises a low-duty-ratio V-shaped groove grating, a multimode interference coupling beam splitting waveguide, a gain waveguide array, a multimode interference coupling beam combining waveguide, a high-duty-ratio V-shaped groove grating and a micro conical waveguide which are sequentially arranged in the second direction and connected. According to the invention, the high-power narrow-linewidth semiconductor laser facing the quantum gyroscope is realized on the premise of reducing the structural complexity of the device.

The invention relates to the technical field of optical fibers, in particular to a double-cladding single-mode strain optical fiber which comprises a fiber core, an inner cladding and an outer cladding, and a middle layer and a leakage layer are arranged between the inner cladding and the fiber core. The refractive index of the middle layer is lower than that of the fiber core, a refractive index barrier is formed, and a light field is limited from diffusing out of the fiber core; the refractive index of the leakage layer is equal to that of the fiber core, a leakage channel is provided for a high-order mode, the high-order mode cannot meet the total reflection condition due to the insufficient incident angle and can permeate into the leakage layer and be lost, only a fundamental mode (LP01) can be stably transmitted in the fiber core, and the phenomenon that when a laser and an amplifier carry out high-power laser output, the high-order mode is damaged is avoided. The invention solves the problem that the improvement of the laser power and the beam quality are limited due to the fact that the double-cladding single-mode strain optical fiber is easily influenced by nonlinear effects such as stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), meanwhile, the problem of multimode interference is avoided, and the improvement of the laser power and the beam quality in the double-cladding single-mode strain optical fiber and the high stability and low mode field distortion of single-mode transmission are ensured.

This invention provides a monolithically integrated semiconductor master oscillator power amplifier laser, relating to the field of semiconductor optoelectronics technology. The laser comprises a master oscillator region and a power amplifier region integrated on the same substrate using standard semiconductor active region technology; the power amplifier region employs an active 1×1 multimode interference coupler structure; and the laser adopts a monolithically integrated structure. This invention can improve the problem of beam flattening, thereby facilitating coupling with optical fibers or waveguide devices, simplifying the system coupling process, and enabling large-scale production applications.

This invention belongs to the field of microwave antenna and RF front-end circuit technology, specifically relating to a broadband filter dielectric resonator antenna with wide harmonic suppression characteristics and a method for controlling its radiation characteristics. The method includes the following steps: obtaining an initial electromagnetic state parameter set and performing fundamental mode field distribution decoupling calculations; constructing an open-loop feeder partially coupled topology to generate a hybrid broadband response signal set; parsing the passband envelope and attenuation determination to map a folded open-loop resonator to generate lower stopband zeros; determining the harmonic frequency band energy density threshold to trigger a multi-topology notch filter to generate an upper stopband zero array; and compensating for phase group delay and gain flatness to output the converged final radiation state parameters of the antenna. This invention overcomes the problems of multimode interference between the feed network and the radiator, the inability to independently generate stopband radiation zeros, and nonlinear phase group delay shift caused by the lack of distributed notch filter node cooperative configuration.

The invention relates to an optical splitter chip, a preparation method of the optical splitter chip and optical equipment. According to the optical splitter chip provided by the invention, an optical waveguide core layer comprises a first optical splitting structure, an optical splitting assembly and an output waveguide assembly; the light splitting assembly comprises at least one column of light splitting array; each column of light splitting array comprises a plurality of sub light splitting structures; any light splitting structure comprises an input waveguide, a multi-mode interference waveguide and a plurality of output waveguides; each output waveguide of the first light splitting structure is coupled with an input waveguide of one sub light splitting structure in the first column of light splitting array through a transition waveguide; each output waveguide of each sub-light-splitting structure in each column of light-splitting array is coupled with an input waveguide of one sub-light-splitting structure in the next column of light-splitting array after the sub-light-splitting structure in each column of light-splitting array through a transition waveguide; and each output waveguide of each sub light splitting structure in the last column of light splitting array is coupled with one final output waveguide in the output waveguide assembly, so that the channel expansion capability is improved.

A power splitter may include a single-core optical fiber, a beam-splitting optical fiber, and a multicore optical fiber. The beam-splitting optical fiber may include a polygonal core configured to output a multimode interference beam pattern including a plurality of beam spots, an input end coupled to the single-core optical fiber, and an output end coupled to the multicore optical fiber. In embodiments, a difference between a mode field diameter of the cores of the multicore optical fiber and a mode field diameter of the core of the single-core optical fiber may be less than or equal to 50%. In embodiments, when the power splitter is in operation, a difference between a distance between neighboring beam spots of the multimode interference beam pattern output by the beam-splitting optical fiber and a core pitch of the cores of the multicore optical fiber may be less than or equal to 10%.

Structures for a polarization splitter and methods of forming such structures. The structure comprises a multimode interference structure including a first multimode interference region, a second multimode interference region, a first waveguide core adjoined to a first portion of the first multimode interference region at a first acute angle, a second waveguide core adjoined to a second portion of the first multimode interference region at a second acute angle, and a third waveguide core adjoined to a third portion of the first multimode interference region. The second multimode interference region has an overlapping relationship with the first multimode interference region.

The application provides an optical multimode interference coupler. The optical multimode interference coupler of the application directly connects a transmission waveguide with a slit structure and a bar-shaped multimode waveguide at an interface, and based on multimode excitation principle and self-imaging principle of the multimode interference coupler, the optical signal in the bar-shaped multimode waveguide is simultaneously split and the waveguide structure is converted at the interface in the slit single-mode waveguide, without using a traditional tapered bar-slit waveguide conversion structure, so that the length of the electronic component is effectively reduced and the integration of the component is improved. The application realizes that the input optical signal can be directly and evenly divided into two slit waveguides from the bar-shaped waveguide, without using a traditional combination structure of splitting light first and then converting. The device has the advantages of small size, low loss, high bandwidth and the like.

The invention is entitled "VCSEL array for HAMR." The present disclosure relates to the pre-processing of a magnetic recording head for a magnetic media drive. For a heat-assisted magnetic recording (HAMR) head, an optical source provides the heat necessary for the drive operation. A vertical cavity surface emitting laser (VCSEL) is mounted to the top surface of the slider. A plurality of laser beams are emitted from the bottom surface of the VCSEL and are directed to a corresponding number of waveguide structures within the HAMR head. The waveguide structures feed into a multimode interference (MMI) device which then directs the laser light into a single waveguide to be focused on a near-field transducer (NFT). The VCSEL laser is phase coherent and does not have mode hopping.

This invention discloses an on-chip adjustable intensity equalization 90-degree optical mixer and its design method. The device is arranged along the optical path as follows: an input fan-in structure, an input tapered transition structure, a 4×4 multimode interference region, an output tapered transition structure, and an output equal-path fan-out structure. The output equal-path fan-out structure incorporates an on-chip adjustable intensity equalization structure. The four output branches of the output equal-path fan-out structure are each integrated with the on-chip adjustable intensity equalization structure. An asymmetric tapered input adjusts the incident mode field to satisfy the MMI four-image self-image condition. The 4×4 multimode interference region generates two sets of four-way mixed output beams with a 180° phase difference and 90° orthogonality between sets. This invention independently controls the electrically controlled transmittance of each output path through the on-chip adjustable intensity equalization structure, dynamically compensating for output power imbalances caused by fabrication, packaging, and environmental drift, thereby improving balanced detection performance.

The invention discloses a mode multiplexing demultiplexer based on a sub-wavelength grating and a preparation method thereof, and relates to the technical field of optical communication and optical interconnection. The mode multiplexing and demultiplexing device comprises a first-stage multi-mode interference coupler, a second-stage multi-mode interference coupler, a third-stage multi-mode interference coupler, a fourth-stage multi-mode interference coupler, a fourth-stage multi-mode interference coupler and a fifth-stage multi-mode interference coupler, the second-stage multimode interference coupler is cascaded to the output end of the first-stage multimode interference coupler and is used for realizing mode conversion and forming a second-order image of the output waveguide; the double-arm phase shifter is integrated between the first-stage multi-mode interference coupler and the second-stage multi-mode interference coupler and is used for introducing a fixed phase difference in the optical transmission process; wherein a sub-wavelength grating structure is integrated in each of the first-stage multimode interference coupler, the second-stage multimode interference coupler and the double-arm phase shifter. According to the mode multiplexing and demultiplexing device, the excellent performance of wide bandwidth, low loss and low crosstalk can be realized under the condition of ultra-compact size.

The present disclosure provides an optical computing based storage and operation device and an optical computing device. The storage and operation device comprises one or more phase shift units, each configured to apply a phase shift amount to a corresponding optical signal to shift the phase of the optical signal, wherein the phase shift unit comprises a phase change material configured to maintain a refractive index unchanged in case that an external excitation applied thereto is reduced or removed, and the applied phase shift amount is determined by the refractive index of the phase change material; and one or more multimode interference units, each configured to cause a corresponding plurality of input optical signals to perform multimode interference to generate a plurality of output optical signals, wherein at least one of the plurality of input optical signals is an optical signal shifted in phase via a corresponding phase shift unit.

This application relates to the technical field of photonic integrated circuits, and discloses a chip structure and method for enhancing local evanescent wave optical fields. The chip structure includes multiple stages of cascaded multimode interference couplers (MMCs). Each MMC includes an input waveguide, a multimode waveguide region, and an output waveguide. The output waveguides of each final stage MMC are connected via loop waveguides, and a phase modulator is mounted on the loop waveguides. The multiple loop waveguides of the multiple MMCs form a waveguide array region. This application has the advantage of improving imaging resolution, and the structure has a simple process and low manufacturing cost.

The application discloses a high-dimensional light field detection method based on physical feature decoupling, and belongs to the technical field of optical measurement. The method comprises the following steps: S1, collecting a speckle pattern of a to-be-detected high-dimensional light field encoded and output by a multimode interference medium; S2, performing light field physical feature separation and denoising processing on the speckle pattern, projecting a plurality of light field parameters of the to-be-detected high-dimensional light field into respective corresponding low-dimensional feature subspaces, and obtaining low-dimensional features corresponding to the plurality of light field parameters of the to-be-detected high-dimensional light field; and S3, inputting a feature vector composed of the low-dimensional features into a decoding module based on a physical feature subspace which is pre-established and trained, and obtaining the plurality of light field parameters of the to-be-detected high-dimensional light field. The application further discloses a high-dimensional light field detection device based on physical feature decoupling. The application can effectively improve the detection sensitivity and stability of subtle changes in the light field, reduce the demand for training data and the complexity of the model, and reduce the training and reasoning time.

A power splitter may include a single-core optical fiber, a beam-splitting optical fiber, and a multicore optical fiber. The beam-splitting optical fiber may include a polygonal core configured to output a multimode interference beam pattern including a plurality of beam spots, an input end coupled to the single-core optical fiber, and an output end coupled to the multicore optical fiber. In embodiments, a difference between a mode field diameter of the cores of the multicore optical fiber and a mode field diameter of the core of the single-core optical fiber may be less than or equal to 50%. In embodiments, when the power splitter is in operation, a difference between a distance between neighboring beam spots of the multimode interference beam pattern output by the beam-splitting optical fiber and a core pitch of the cores of the multicore optical fiber may be less than or equal to 10%.

The application discloses a large-bandwidth silicon-based optical splitter with adjustable splitting ratio based on a subwavelength grating structure. The device comprises a first-stage 1*2 multimode interference coupler (I), a thermal phase shifter (II) and a second-stage 2*2 multimode interference coupler (III). A first input waveguide is connected with two arms of the thermal phase shifter through the first-stage 1*2 multimode interference coupler, the two arms of the thermal phase shifter are connected with the second-stage 2*2 multimode interference coupler respectively, and the second-stage 2*2 multimode interference coupler is connected with a first output waveguide and a second output waveguide respectively. The thermal phase shifter comprises two phase-shifting areas composed of a subwavelength grating wide waveguide and a silicon continuous wide waveguide, and a metal electrode is arranged above the two phase-shifting areas. The application realizes the large-bandwidth optical splitter with adjustable splitting ratio, and has the advantages of high performance, simple process and easy expansion.

An optical structure comprisinga multimode interference waveguide section, the multimode interference waveguide section comprising an input face, an output face and sidewalls extending therebetween, the sidewalls extending substantially parallel to a length axis;at least one input optical waveguide abutting the input face and spaced apart from the sidewalls;at least one output optical waveguide abutting the output face and spaced apart from the sidewalls;the input face being divided into first and second input face shoulder portions arranged on opposite sides of the at least one input optical waveguide; andthe output face being divided into first and second output face shoulder portions arranged on opposite sides of the at least one output optical waveguide;the optical structure further comprising at least one external reflector appendage, the at least one external reflector appendage comprising a reflector portion integrally extending from a shoulder portion and an appendage waveguide integrally extending from the reflector portion along an axis inclined to the length axis, the reflector portion comprising a reflector wall arranged such that light travelling parallel to the length axis which is incident on the reflector wall is reflected into the appendage waveguide.

The invention provides a receiving and transmitting integrated optical phased array chip based on grating lobe demodulation, which relates to the technical field of photon integrated circuits and comprises an optical input end, a multimode interference beam splitter, a transmitting phase shifter array, a transmitting grating antenna array, a receiving grating antenna array, a receiving phase shifter array, an equal-length waveguide array, a star coupler and a receiving channel. Wherein the multimode interference beam splitter, the star coupler, the transmitting and receiving phase shifter array, the pair of coaxial receiving and transmitting grating antenna arrays with mismatched array spacing and the equilong array waveguides form a deep coupling and indispensable collaborative design chip structure, so that a parallel transmitting and receiving function based on grating lobe demodulation is realized. According to the receiving and transmitting integrated optical phased array chip based on grating lobe demodulation, the main lobe and the grating lobe are demodulated to different channels, the problem that a traditional OPA cannot utilize grating lobe energy is solved, parallel receiving and transmitting distance measurement based on grating lobe demodulation is achieved, the control complexity is reduced, and the light energy utilization efficiency is improved.