249 results about "Effective refractive index" patented technology

The invention relates to a high-efficiency super lens based on refractive index matching and a design method thereof. The super lens comprises a super atom structure layer and a bonding substrate layer on any surface, the difference value between the refractive index of any substrate layer and the average effective refractive index of the super-atomic structure layer is smaller than a preset value; when the super lens is designed, the relation among the average effective refractive index, the impedance and the S parameter of the super-atom structure layer is constructed, the structure parameter of the super-atom structure layer is determined based on the requirement parameter of the super lens, the preset S parameter of the super-atom structure layer is obtained based on electromagnetic simulation, and the average effective refractive index of the super-atom structure layer is calculated. And the substrate layer is used as an expected refractive index matching material and is bonded on one surface or two surfaces of the super-atomic structure layer. According to the invention, the high-efficiency super lens is obtained by using the principle of refractive index matching and processing methods such as large-area bonding, the focusing efficiency of the super lens is greatly improved, the application of the super lens is promoted, and the leap-type upgrading of optical devices in the dimensions of light weight and high performance is realized.

The invention discloses a polarization insensitive filter based on a sub-wavelength grating structure, and belongs to the technical field of integrated photonic devices. The filter comprises an input transition waveguide, a multimode waveguide grating and an output transition waveguide which are connected in sequence. The multimode waveguide grating is composed of a central sub-wavelength grating waveguide and Bragg gratings symmetrically distributed on the two sides, and the effective refractive indexes of TE polarization and TM polarization are equal by adjusting the waveguide width and duty ratio of the central sub-wavelength grating, so that the polarization sensitivity of the device is eliminated fundamentally. And the input / output transition waveguide adopts a transition mode of mixing a tapered waveguide and a sub-wavelength grating waveguide, so that low-loss mode transmission between a straight waveguide and a multimode grating is realized. According to the invention, the anisotropic equivalent medium characteristic of the sub-wavelength grating is utilized, a function of simultaneously and effectively filtering TE and TM polarization is realized, and the filter has the advantages of polarization insensitivity, flexible design, compact structure, simple process and compatibility with a CMOS (Complementary Metal Oxide Semiconductor) process, and has important application value in the fields of optical communication, optical interconnection and the like.

The invention discloses a super-lens design method based on etching uniformity compensation and an optimization system thereof. The super-lens design method specifically comprises the following steps: S1, etching a wafer and establishing an etching rate space distribution model; S2, designing layout partitions and distributing compensation coefficients; s3, pre-compensating the size of the nano structure; s4, generating a final mask and executing etching; according to the method, the space size pre-compensation of the nano structure is actively performed in the mask design stage, and the phase deviation caused by non-uniform etching depth is counteracted by using the change of the effective refractive index of the nano unit, so that the high-performance super lens is obtained under the non-ideal process condition, and the limitation of the process physical limit is broken through.

An optical device includes a transition unit in which a first waveguide and a second waveguide are disposed in an overlapped manner such that a magnitude relationship of an effective refractive index between the vertical modes propagating the first waveguide and the vertical modes propagating the second waveguide is inverted at the positions of input and output. The transition unit allows, at the input, the second waveguide to be a single mode waveguide and allows, at the output, the second waveguide to be a multi-mode waveguide through which TM0 light in the maximum vertical mode and light in a higher-order mode propagate. The optical device includes a removing unit that allows the second waveguide to be a single mode waveguide through which the TM0 light propagates by removing the light in the higher-order mode from the light received from the transition unit.

The invention relates to an optomechanical system for monitoring the mechanics of a sample, comprising: a photonic crystal (1, 2) with a substrate (1) and an array of transversally extending nanopillars (2) defining at least one row (3); a nanopillar cavity (4) for confining light and acting as a sensor for the sample; and a mirror region (5) formed in the array of nanopillars (2), the cavity (4) and the mirror region (5) being configured to prevent the propagation of light with Transverse-Magnetic (TM) polarization; the nanopillars (2) being spatially arranged to create a gradient of effective refractive index along the cavity (4), the maximum value of the effective refractive index inside the cavity (4) being lower than the effective refractive index of the mirror region (5).

An optical communication system can include a multiplexer / demultiplexer. The multiplexer / demultiplexer can transfer a first optical data signal between a first single-mode fiber and a first propagation mode of a few-mode fiber. The first propagation mode can have a first effective refractive index. The multiplexer / demultiplexer can transfer a second optical data signal between a second single-mode fiber and a combination of a second propagation mode of the few-mode fiber and a third propagation mode of the few-mode fiber. The second propagation mode and the third propagation mode can have a same effective refractive index that differs from the first effective refractive index. During propagation within the few-mode fiber, the second optical data signal can couple bidirectionally between the second propagation mode and the third propagation mode, while being substantially isolated from the first optical data signal in the first propagation mode.

The present invention discloses a fiber-optic ultrasonic endoscope with integrated lateral transmission and reception and a preparation method, which belongs to the field of ultrasonic endoscopic imaging. It comprises a double-clad optical fiber, an excitation film, a dielectric mirror, and a sensing film. By etching part of the inner cladding of the optical fiber into a concave spherical surface and coating it with an excitation film, the excitation light transmitted in the inner cladding is absorbed and focused ultrasonic waves transmitted laterally are excited. By etching part of the inner cladding and the core of the optical fiber and preparing it into a Fabry-Perot (F-P) cavity. When the ultrasonic signal transmitted laterally into the ultrasonic endoscope acts on the sensing film of the cavity, the effective refractive index of the sensing film and the F-P cavity length change, and the signal light in the core demodulates this change to complete the detection of ultrasonic waves. The present invention etches the inner cladding and coats it with an excitation film to achieve the excitation of laterally focused ultrasonic waves, etches an F-P cavity on the side of the optical fiber to achieve the lateral detection of ultrasonic waves, and thus forms a fiber-optic ultrasonic endoscope with integrated lateral transmission and reception.

The invention provides a novel perovskite cell and a preparation method thereof, the novel perovskite cell comprises an antireflection film stack layer, a glass substrate, an equivalent refraction layer, a hole transport layer, a perovskite layer, an electron transport layer and a top electrode which are arranged in sequence, the antireflection film stack layer is used for constructing refractive index transition between air and the glass substrate, and the hole transport layer is used for transmitting the hole transport layer. The absolute amount of effective light entering the battery is increased; the target effective refractive index of the equivalent refraction layer is associated with the first refractive index of the glass substrate and the second refractive index of the hole transport layer, and is used for constructing refractive index transition between the glass substrate and the hole transport layer so as to reduce the interface reflection loss of the perovskite cell; it is ensured that incident light passing through the glass substrate penetrates to the perovskite layer without significant loss. Through the superposition design, the utilization rate of light in the battery can be effectively improved, and the power generation efficiency of the battery is further improved.

The invention provides a post-manufacturing correction method based on a chalcogenide phase change material, and belongs to the field of optical communication. The method comprises the following steps: firstly, taking the surface of a silicon photonic device as a substrate layer, depositing a monocrystalline silicon material on the substrate layer, and etching a groove structure on the monocrystalline silicon material to form a silicon waveguide; secondly, sequentially depositing a chalcogenide phase change material film, an isolation layer, a resistance heating layer, an adhesion layer and a metal electrode layer on the silicon waveguide; and finally, an electric pulse is applied to the resistance heating layer to generate Joule heating, the refractive index of the chalcogenide phase change material film above the silicon waveguide is finely adjusted, the effective refractive index of the waveguide is changed, the phase of an optical signal is modulated, and the phase adjustment range is 0-pi. The phase correction mode has the characteristics of low insertion loss, high correction precision and multi-stage finishing, is simple in structure, can reduce the production cost, is suitable for CMOS (Complementary Metal-Oxide-Semiconductor Transistor) integration, is easy to match with a modern semiconductor process production line, and is suitable for industrial production and productization.

A photonics device including a waveguide and an index smoothing structure is described. The waveguide is configured to carry an optical signal and includes a thin film lithium-containing electro-optic (TFLCEO) material. The waveguide has a first portion, a transition portion, and a second portion. The optical signal has a first mode in the first portion and a second mode in the second portion. The transition portion transfers the optical signal between the first portion and the second portion and transitions between the first mode and the second mode. The index smoothing structure corresponds to the transition portion. The index smoothing structure is configured to transition a first effective index of refraction for the first mode to a second effective index of refraction for the second mode. The index smoothing structure having an intermediate effective index of refraction.

The embodiment of the invention provides a multi-physical field collaborative simulation method and device for a high-speed silicon-based electro-optical modulator, and the method comprises the steps: building a physical model of the electro-optical modulator, carrying out the simulation under different bias voltage and temperature conditions, solving a Poisson equation, a carrier continuity equation and a drift diffusion transport equation, and obtaining the corresponding carrier concentration distribution; performing small-signal simulation analysis on the model to obtain corresponding PN junction electrical characteristic parameters; performing waveguide optical mode simulation on the model to obtain corresponding electric field mode distribution and effective refractive index, and calculating the effective refractive index and absorption coefficient change of the waveguide; constructing a traveling wave electrode model, simulating the traveling wave electrode model to solve an S parameter of a traveling wave electrode, and determining a distribution parameter of the no-load traveling wave microstrip line; a load traveling wave transmission line model is constructed in combination with PN junction electrical characteristic parameters, and based on the model, the frequency response characteristics and the modulation bandwidth of the electro-optical modulator at different temperatures are determined, so that the accuracy of a simulation result can be improved.

A dynamically tunable optical mirror named as a resonant cavity switching (RCS) device and a refractive index modulating (RIM) device are disclosed. The RCS device is comprising a nanoporous piezoelectric III-nitride material layer, such as GaN, AlN, AlScN, AlGaScN or their alloys sandwiched between a high-reflectivity distributed Bragg reflector (DBR) and a lower-reflectivity output DBR. The RIM devise is comprising the nanoporous III-nitride material layer. The nanoporous layer, patterned with interdigital transducers (IDTs), is actuated via surface acoustic waves (SAWs) or electric fields to induce rapid, reversible modulation of its effective refractive index. This enables sub-nanosecond switching between resonant and off-resonant optical states, facilitating efficient energy extraction, optical pulse carving, or phase control.

A waveguide assembly includes first and second waveguides. The first waveguide includes silicon, first and second ends, an end member, and a tapered member. The end member extends from the first end. The tapered member extends from the end member to the second end. The second waveguide is optically coupled to and spaced away from the first waveguide. The second waveguide includes silicon nitride, first and second members, and a non-tapered member. The non-tapered member extends from the first member to the second member and in parallel with and opposing the tapered member. An effective refractive index of the non-tapered member matches an effective refractive index of the tapered member at a first plane. The first plane extends through the non-tapered member and the tapered member and perpendicular to a second plane. The second plane extends parallel to a direction of overlap between the first and second waveguides.

To provide an onium salt used for a chemically amplified resist composition excellent in solvent solubility, having high sensitivity and high contrast, and excellent in lithography performance such as LWR, CDU, MEF, EL and DOF in photolithography using high energy rays, a chemically amplified resist composition containing the onium salt, and a pattern forming method using the chemically amplified resist composition.SOLUTION: An onium salt having the formula (1): SELECTED DRAWING: None

The application provides a wavelength division multiplexer and a silicon optical chip, which comprises a first unit and at least one second unit; the first unit is connected with each second unit through a first waveguide; an output port and a plurality of output ports are arranged on the same side of the first unit; the first unit and the plurality of second units are each provided with a wavelength interleaver; the wavelength interleaver comprises a homogeneous waveguide and a heterogeneous waveguide; the heterogeneous waveguide comprises a main body composed of a first material; a gap is arranged in the main body; the gap is filled with a second material; along the propagation direction of input light, the wavelength interleaver is provided with an input section, an input coupling section, a phase difference accumulation section, an output coupling section and an output section; the effective refractive index of the homogeneous waveguide and the effective refractive index of the heterogeneous waveguide in the phase difference accumulation section are different. The wavelength division multiplexer can be applied to the manufacture of optoelectronic devices, such as a silicon optical chip. The first unit and the second unit are in a folded layout, so that the layout of the wavelength division multiplexer on the chip is compact and modular.

The invention relates to a mode field separation high-polarization semiconductor laser and application thereof, and aims to solve the problem of low polarization degree caused by stress of an existing laser. The laser comprises a main mode field region and a coupling region which are stacked along an epitaxial growth direction. The main mode field region is used for limiting and lasing a first polarization optical mode; the coupling region is made of a high-loss material and is used for absorbing and attenuating the second polarization optical mode. The two meet the following matching conditions: the effective refractive index of the second polarization optical mode of the coupling region is matched with the effective refractive index of the specific m-order second polarization optical mode of the main mode field region, so that the second polarization optical mode is optically coupled and expanded to the coupling region to be dissipated; the effective refractive index of the first polarization optical mode of the coupling region is mismatched with the effective refractive index of the specific m-order first polarization optical mode of the main mode field region, so that the coupling region is limited in the main mode field region for stable lasing. According to the invention, a polarization-related mode filtering mechanism is utilized, so that the polarization degree and the process robustness of the laser are remarkably improved.

A semiconductor light-emitting structure includes a semiconductor substrate layer, a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer, and a second limiting layer stacked in sequence. The active layer comprises a first superlattice active layer and a second superlattice active layer stacked in sequence, and the second superlattice active layer is located on a side of the first superlattice active layer away from the first waveguide layer. The semiconductor light-emitting structure further includes an insertion layer disposed between the second superlattice active layer and the first superlattice active layer. A refractive index of the insertion layer is less than an effective refractive index of the first superlattice active layer and less than an effective refractive index of the second superlattice active layer.

The invention discloses an infrared super lens with a moth eye imitating anti-reflection nano structure. The moth-eye anti-reflection metasurface, the metasurface lens and the substrate are all made of silicon materials, and the moth-eye anti-reflection metasurface and the metasurface lens are micro-nano-scale arrays and are located on the two sides of the same substrate respectively. According to the invention, the metasurface is fully utilized to finely and efficiently modulate the phase, amplitude and other characteristics of light waves, the moth-eye metasurface changes the effective refractive index of the surface and reduces the reflectivity of incident light on the silicon surface, the metasurface lens enables the phase distribution to meet the spherical wavefront contour, efficient focusing of emergent beams is realized, and the light quality is improved. All micro-nano structures have the advantage of good thermal stability based on the same substrate material, and anti-reflection and focusing effects are achieved in an extremely thin scale.

The invention discloses a dual-wavelength frequency doubling regulation and control method based on a PPLN waveguide, and relates to the technical field of nonlinear optics. The method comprises the following steps: constructing a PPLN waveguide model, and determining a fundamental frequency light mode and a frequency doubling light mode; calculating effective refractive indexes of the fundamental frequency light and the frequency doubling light at respective wavelengths; the polarization period is calculated according to the effective refractive index, any target polarization period is fixed, the target polarization period is configured to correspond to two different working wavelengths at the same time, and therefore dual-wavelength frequency doubling light with a specific wave crest interval is generated at the output end of the waveguide; the wave crest interval is regulated and controlled by selecting different polarization periods; according to the invention, dynamic control of dual-wavelength frequency multiplication output is realized by changing the size of a polarization period; the single waveguide can complete various optical function design ideas, and has certain value for research in related fields such as multi-wavelength lasers and wavelength multiplexing communication.

The invention discloses a bending endoscopic imaging method and system based on a few-mode optical fiber, and belongs to the technical field of optical fiber imaging. According to the method, an MNIST handwritten digital image is loaded through a digital micromirror device (DMD), a speckle pattern is generated through few-mode optical fiber transmission, image restoration in a bending state is achieved through a deep learning model, and reconstruction effects under different bending degrees are quantized through a Dice coefficient. The system comprises a light beam collimation module, a pattern loading module, an image transmission module and an image acquisition-processing module. The image transmission module adopts a step refractive index few-mode optical fiber, and mode coupling caused by bending is inhibited by increasing the effective refractive index difference between modes; and the image acquisition-processing module is combined with a shallow U-shaped convolutional neural network to reconstruct a speckle pattern acquired by the CCD camera. While miniaturization of the probe is ensured, the imaging quality in a bending environment is remarkably improved, and the probe is suitable for miniaturized high-resolution imaging scenes such as medical endoscopes and the like.

The application discloses a kind of bound state thin film lithium niobate optical filter based on quasi continuum body.The optical filter is sequentially stacked from top to bottom by tunable filter layer, thin film lithium niobate flat plate, dielectric buried oxygen layer and substrate layer, heating electrode and reflective grating are distributed on both sides of waveguide, periodically arranged reflective grating is arranged between heating electrode and waveguide, the width of waveguide is set to realize bound state in continuum, reduce the lateral leakage loss caused by mode leakage, reflective grating is used to reflect the mode leaked into lithium niobate flat plate back to waveguide to further realize bound state in quasi continuum, heating electrode is used to change the effective refractive index of reflective grating.The application is easy to process, has large tolerance, low loss, and can effectively realize low-loss, narrow-bandwidth photonic filtering, by changing the voltage loaded on the heating electrode to control the center wavelength of the filter without changing the physical structure, filters with different reflection center wavelengths can be realized.

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 present invention proposes a fitting method for the ultra-low reflectivity of optical coatings to solve the technical problem of large measurement errors in the ultra-low reflectivity of optical coatings. The steps of the present invention are as follows: simulating and calculating the effective refractive index of the waveguide of an uncoated FP laser chip at both ends to obtain the reflectivity of the uncoated FP laser chip and air; performing a P-I test on the uncoated FP laser chip at both ends to obtain a threshold current; performing an ultra-low optical coating on one end of the uncoated FP laser chip to obtain a laser chip with one end coated; applying different current values ​​to the laser chip with one end coated according to the threshold current and testing the corresponding spectral curves; using the spectral curves under different current values, the reflectivity of the ultra-low optical coating is obtained according to the reflectivity fitting. The present invention can accurately estimate the ultra-low reflectivity of the optical coating, playing a decisive role in the optimization of SLD and SOA products.

The invention relates to the field of optical fibers, in particular to a D-type optical fiber based on Fe3GaTe2 nanosheets and a preparation method and application of the D-type optical fiber. The invention discloses a D-type optical fiber based on a Fe3GaTe2 nanosheet. The D-type optical fiber comprises a D-type optical fiber and a Fe3GaTe2 layer deposited on a D-type plane of the D-type optical fiber. By utilizing the evanescent field characteristic of the D-type optical fiber, the Fe3GaTe2 nanosheet is deposited on the D-type plane of the D-type optical fiber, and magnetic anisotropy change (such as magnetization direction switching) is generated under the action of an external magnetic field, so that the effective refractive index of the optical fiber is changed; the change is converted into an optical path difference in the Michelson interferometer. Finally, the magnetic field intensity can be inverted by measuring the FSR change of the interference spectrum. The room-temperature MA adjustability of the Fe3GaTe2 nanosheets provides a larger refractive index change range (superior to that of magnetic fluid), and the nanosheets are not easy to degrade, so that the D-type optical fiber has higher sensitivity and temperature performance.

Disclosed are apparatuses for optical coupling and a system for communication. In one embodiment, an apparatus for optical coupling having an optical coupling region is disclosed. The apparatus for optical coupling includes a substrate and a core layer disposed on the substrate. The core layer includes a plurality of holes located in the optical coupling region. An effective refractive index of the core layer gradually decrease from a first end of the optical coupling region to a second end of the optical coupling region.

This application provides an optical filter, a wavelength division multiplexing (WDM) device, and an optical quantum computer, relating to the field of integrated optics. The optical filter provided in this application is configured based on the Mach-Zehnder interferometer principle and has two waveguides, each containing multiple phase shifters. To overcome manufacturing and temperature errors in the optical filter, the lengths of the aforementioned phase shifters are constrained so that the sum of the product of the effective refractive index fluctuations of the phase shifters on both sides under temperature changes and their lengths is equal, and the sum of the product of the effective refractive index fluctuations of the phase shifters under width changes and their lengths is also equal. This overcomes the influence of manufacturing and temperature fluctuations on the optical filter, improving its stability. Furthermore, considering the solvability of the aforementioned constraints, the aforementioned phase shifters can have at least three waveguide widths (preferably four) to ensure that the aforementioned constraints can be practically achieved.

A vertical cavity surface emitter (VCSEL) has a body comprising a vertical stack of stacked semiconductor layers, including: a current-limiting region enclosing a low-resistance current-flow region defined by a high-resistance current-flow region, and a first epitaxial sublayer located near the current-limiting region, wherein the first epitaxial sublayer includes a projection or recess defining a main cavity, and the remainder of the first epitaxial sublayer defines an outer cavity;wherein the projection or recess is defined by a physical step h which is predetermined according to the following equation: qλ0 - mλ1 = n0 h where λ0 is a resonant wavelength of the light in the main cavity, λ1 is a resonant wavelength of the light in the outer cavity, q is a positive half-integer, n0 is the effective refractive index in the main cavity, and m is a constant.;

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.

An electrically switchable liquid crystal cell (10) is provided together with a lens (50) having this liquid crystal cell, and a method for manufacturing the liquid crystal cell. The liquid crystal cell (10) has a diffractive optical element (12) and a liquid crystal material (14) that can be switched between a mismatched (unswitched) state and a matched (switched) state. In the mismatched state, the effective refractive index of the liquid crystal material (14) is different from the effective refractive index of the substrate (18) of the diffractive optical element (12). In the matched state, the effective refractive index of the liquid crystal material (14) matches the effective refractive index of the substrate (18). In the matched state, the diffractive optical element does not contribute to the focal power of the lens. The diffractive optical element (12) has a number of peaks (20) and valleys (30) with rounded corners.

This invention relates to the field of optical waveguide technology, specifically providing a method for driving a liquid crystal waveguide beam scanner. The method involves calculating the director of liquid crystal molecules under an applied electric field, calculating the dielectric tensor based on the director, obtaining the effective refractive index of the optical waveguide based on the dielectric tensor, calculating the scanning angle under different applied electric fields, establishing the dynamic relationship between the scanning angle and voltage, and designing a driving voltage waveform accordingly to achieve a preset beam scanning process. This invention enables precise and predictable beam scanning, fulfilling specific application requirements.