10 results about "Coupling length" patented technology

The invention discloses a polarization independent mode multiplexing / demultiplexing device based on a transverse sub-wavelength grating structure, and belongs to the technical field of photoelectrons. The device adopts an asymmetric directional coupler structure and mainly comprises a bus waveguide formed by a transverse sub-wavelength grating waveguide and a coupling waveguide parallel to the bus waveguide. The core is that longitudinal sub-wavelength grating waveguides with specific duty ratios are introduced to the coupling side of a bus waveguide and the two sides of a coupling waveguide, and accurate matching of dual-polarization-state effective refractive indexes and coupling lengths is achieved through combined regulation and control of geometric parameters of transverse and longitudinal gratings. And the dual-polarization fundamental mode in the coupling waveguide and the dual-polarization same-order high-order mode in the bus waveguide can realize synchronous conversion in a coupling region. The invention overcomes the defect of strong polarization correlation of the traditional device, has the advantages of polarization independence, low crosstalk, low insertion loss, compact structure, high process tolerance, easiness in mode expansion and the like, and can be used for multi-dimensional multiplexing transmission in optical communication and optical interconnection systems.

A mode insensitive 2x2 thermo-optic switch for mode division multiplexing system belongs to the technical field of planar optical waveguide devices. It is composed of a silicon substrate, a silicon dioxide lower cladding layer, a polymer core layer waveguide and a polymer upper cladding layer. The polymer core layer waveguide is composed of a first input straight waveguide and a second input straight waveguide, a first input S curved waveguide and a second input S curved waveguide, a first coupling arm straight waveguide, a second coupling arm straight waveguide and a third coupling arm straight waveguide, a first output S curved waveguide and a second output curved waveguide, and a first output straight waveguide and a second output straight waveguide. A metal modulation electrode is prepared on the polymer upper cladding layer corresponding to the second coupling arm straight waveguide. The present application realizes the channel switching of LP 01 , LP 11a and LP 11b three modes by adjusting the spacing and coupling length of the coupling arm straight waveguide and whether to apply the modulation electrode, which has important significance in the field of mode division multiplexing applications.

This application discloses a method, apparatus, storage medium, and lidar for obtaining etching depth. The method includes: obtaining a target etching depth corresponding to a target coupling length ratio at the center wavelength of an optical signal, wherein the target etching depth is any metric value selected from multiple etching depths for etching a waveguide; when the target coupling length ratio is the smallest coupling length ratio in the set of ratios, the target etching depth is determined as the waveguide etching depth for etching the waveguide; the set of ratios includes coupling length ratios corresponding to each etching depth in the set of multiple etching depths, and the coupling length ratio is obtained by considering the optical refractive index corresponding to each etching depth and the sensitivity of the optical refractive index to the shift of the center wavelength. Using this application, the operational stability of the optical coupler can be guaranteed, thereby ensuring the stability of the lidar system.

The application discloses a three-dimensional waveguide cross structure, and relates to the technical field of integrated optics and silicon photonics, and comprises a buried oxygen layer, a first material waveguide layer, a first silicon oxide cover layer, a second material waveguide layer and a second silicon oxide cover layer; the effective coupling length of the projection overlapping area of the first material waveguide layer on the second material waveguide layer satisfies the formula: wherein, L represents the effective coupling length, represents a coupling wavelength, and the value range of n is 1 to 2n, wherein n is an integer, and the constant is less than 1. According to the application, the position of the first material waveguide layer relative to the second material waveguide layer is adjusted, so that the power coupling of the cross port of the three-dimensional waveguide cross structure completes an integer multiple of the coupling period in propagation, thereby reducing the loss and crosstalk caused by coupling enhancement.

The invention relates to a high-performance hollow-core anti-resonance optical fiber 3dB beam splitter and a beam splitting method thereof.The 3dB beam splitter comprises a cladding area and a fiber core area, the cladding area is of an anti-resonance structure formed by arranging a plurality of cylindrical quartz glass tubes in a symmetrical mode, transmission of light energy in a fiber core can be effectively limited, and leakage loss can be reduced; the fiber core area is arranged in the cladding area, comprises a first fiber core and a second fiber core and serves as an optical signal transmission channel. When an optical signal enters, the cladding area enables the optical signal to generate X and Y polarized light and to be periodically coupled between fiber cores, the coupling length ratio meets the condition by designing the arrangement of the glass tubes, and polarization-independent 50: 50 beam splitting is achieved. According to the invention, a short beam splitting length and a large bandwidth working range are realized, and a 200nm communication wave band is covered; polarization-independent power beam splitting is accurately realized; the cladding region is simple in structure, high in preparation feasibility and wide in application prospect in the field of optical communication.

The application discloses a cable coupling interference effect test system and method. The system comprises a simulation cable coupling effect test device; the simulation cable coupling effect test device comprises a simulation shielded cable, a receiver, a first cable interface box and a second cable interface box; the simulation cable coupling effect test device is laid within 10 cm of a field interference cable, and the coupling length is greater than 3 m; at least one of the first cable interface box and the second cable interface box adopts a coaxial cable test structure; the coaxial cable test structure is used for measuring the shield layer induced current and the core line coupling voltage of the simulation shielded cable; the receiver is connected with a core line coupling voltage interface and a current probe in a current test cabin to reflect the coupling interference effect level. The application can accurately obtain the shield layer induced current and the cable core line induced voltage generated in the field environment, thereby evaluating the electromagnetic coupling interference level of the field electromagnetic environment on the cable, and providing theoretical data support for field test electromagnetic compatibility.

The invention relates to the technical field of power systems, and discloses a cable effective coupling length analysis method, system and device based on HEMP coupling, a medium and a product, and the method comprises the steps: enabling HEMP plane waves to enter a target cable, considering the dielectric loss characteristics of the ground, determining the actual ground reflection coefficient through the complex dielectric constant of the ground and the incident angle of the HEMP plane waves, and obtaining the effective coupling length of the cable. The method comprises the steps of determining a distribution voltage of a target cable close to an actual scene along a propagation direction, performing time domain analysis on the distribution voltage, determining a coupling signal duration of an HEMP plane wave, and determining an effective coupling length of the target cable according to the coupling signal duration and a propagation speed of the HEMP plane wave along the target cable. Therefore, the measurement precision of the effective coupling length of the cable is remarkably improved, the method can be applied to different types of cables, and a powerful guarantee is provided for safe and stable operation of a power system.

The invention relates to the technical field of photoelectrons, in particular to a high-speed high-responsivity photoelectric detector based on a micro-ring resonant cavity and a preparation method of the high-speed high-responsivity photoelectric detector based on the micro-ring resonant cavity. The waveguide is etched to the N-type InP contact layer of the epitaxial layer structure by adopting a ridge waveguide structure; the micro-ring and the waveguide are arranged side by side, a preset gap width is arranged between the micro-ring and the waveguide to maintain a critical coupling state to form a resonant cavity, and a coupling structure shape design is arranged at a position where the waveguide is close to the micro-ring to increase the coupling length; the electrodes are arranged at the top and the bottom of the micro-ring epitaxial layer structure, and light is absorbed in the whole micro-ring. Therefore, the problem that a traditional PIN photoelectric detector has inherent tradeoff contradiction between responsivity and bandwidth is solved.

The present invention aims to provide a mode conversion device and a design method thereof, which can design arbitrary coupling efficiency and full width at half maximum. The present invention is a mode conversion device having a long-period grating in a core of an optical fiber capable of propagating light in at least two propagation modes, characterized in that the long-period grating satisfies a relationship of mathematical formula C1. Wherein, the full width at half maximum FWHM is a wavelength band in which the coupling efficiency is half compared to the coupling efficiency of the mode conversion of the center wavelength, C is the coupling efficiency, L c is the full coupling length, L g is the grating length, Λ is the grating pitch, and Δβ is the difference in propagation constant of the two propagation modes of the center wavelength as a target of mode conversion; [Mathematical formula C1]

The invention relates to the technical field of power systems, and discloses a method, system, equipment, medium and product for calculating the effective coupling length of a cable under HEMP irradiation, and the method comprises the steps: segmenting a target transmission cable to obtain multiple segments of sub-transmission cables, constructing an HEMP coupling simulation model of the sub-transmission cables for each segment of sub-transmission cable, and calculating the effective coupling length of the cable under HEMP irradiation. The simulation length of the sub-transmission cable is gradually increased according to the preset length step length, the coupling signal response peak value of the HEMP coupling simulation model after HEMP excitation is obtained after the preset length step length is increased every time, and the effective coupling length of the sub-transmission cable is judged according to the coupling signal response peak value change rate of the adjacent preset length step length. And the total effective coupling length of the target transmission cable is determined according to the effective coupling length of each section of sub-transmission cable, so that the accuracy and reliability of calculation of the effective coupling length of the cable under HEMP irradiation are effectively improved.