72 results about "Radiation loss" patented technology

An arc chamber that includes one or more components that include a low thermal conductivity region is disclosed. The low thermal conductivity region may be formed using additive manufacturing to create a lattice pattern, stochastic infill, or hollow void. The low thermal conductivity regions are used to direct the flow of heat to desired areas, such as the faceplate of the arc chamber. The lattice pattern may be located within the end plates of the arc chamber, such that the heat from the cathode and repeller are directed toward the faceplate and away from the bottom of the arc chamber. The lattice pattern may also be located in the side walls and the bottom wall to reduce the amount of heat that is lost to the environment through conduction and radiation.

The invention discloses an optimization method of a low-loss bending waveguide, which comprises the following steps: firstly, adopting NA bending as a basic bending path, determining two optimal boundary NA curves for a given equivalent bending radius Reff, and forming a width gradually-changed NA bending waveguide structure; lateral shift amounts din and dout are introduced into the input end and the output end of the constructed NA bending waveguide structure with the gradually-changed width respectively, and optimal lateral shift amounts din and dout are obtained through step-by-step parameter scanning and simulation optimization; and based on the optimal lateral shift amounts din and dout, obtaining a curved waveguide structure combining an NA curved path, width gradient and a specific lateral shift parameter. According to the method, the mode mismatch loss and the radiation loss can be remarkably reduced at the same time for the NA bending waveguide with the ultra-small radius, and the total transmission loss of the bending waveguide is further reduced on the basis of the prior art.

The utility model discloses a heating plate thermal insulation device for pultrusion, which comprises a heating plate, a pultrusion mold matched with the heating plate is fixedly connected onto the inner wall of the heating plate, heat conduction pipes are mounted on the outer walls of two ends of the heating plate, and a thermal insulation device matched with the heating plate is fixedly connected onto the outer wall of the heating plate. The heating plate heat preservation device for pultrusion is characterized in that the heat preservation device is of a multi-layer composite structure, the multi-layer composite structure comprises a heat preservation plate outer layer, a heat preservation plate middle layer and a heat preservation plate inner layer, and a heating plate plug port is formed in the outer wall of one end of the heating plate. The heat preservation layer is completely attached to the outer wall of the heating plate, the problems of heat preservation dead corners, serious heat loss and the like of the heating plate are solved, the heat preservation layer is of a multi-layer composite structure, heat conduction, convection and radiation loss are effectively prevented, the energy utilization rate is increased, and the pultrusion quality is guaranteed.

The utility model aims to provide a strip line broadband phase shifter. The strip line broadband phase shifter comprises a substrate I, a substrate II and a substrate III, the top surface of the substrate I is integrally covered with a metal layer I, and the bottom surface of the substrate III is integrally covered with a metal layer II; a main line I, a main line II and a Port2 port are respectively arranged on the bottom surface of the substrate I and the top surface of the substrate II; and a main line III, a main line IV, a reference line, a Port 1 port, a Port 3 port and a Port 4 port are respectively arranged on the bottom surface of the substrate II and the top surface of the substrate III. The antenna is small in electromagnetic radiation, is low in radiation loss, is high in anti-interference capability, and can be suitable for occasions where a phased array radar is high in anti-interference capability.

A diffraction grating coupler (10) is provided with: a diffraction grating (12) having a plate-shaped base material (121) and different refractive index regions (122) that are periodically arranged in a one-dimensional or two-dimensional manner within a predetermined range of the base material (121) and have a refractive index different from that of the base material (121); and a light reflecting section (14) provided at an end of the range on the opposite side from the light input section (13) side, the different refractive index region (122) having a planar shape in which the absolute value of the direct coupling coefficient (kappa 1D) is less than 1 / L, the direct coupling coefficient (kappa 1D) is an index indicating the intensity of light traveling from the light input unit (13) in a first direction (positive x-direction) parallel to the base material (121) reflected in the different refractive index region (122) in a second direction (negative x-direction) that differs by 180 DEG from the first direction (positive x-direction) without any radiation loss. The 1 / L is the reciprocal of the span length (L) of the range in relation to the first direction (positive x direction), and the light input portion (13) is a part of the end portion of the range.

The invention provides a bismuth-doped optical fiber and a preparation method and application thereof, the bismuth-doped optical fiber realizes C + L full-band positive gain through cooperation of Bi, Ge, La and Y and component proportion optimization: Bi is a core active component to form a BACS to generate near-infrared gain; la and Y improve the BACS concentration, inhibit non-radiation loss and enhance the gain efficiency; and the Ge adjusts the refractive index of the fiber core to guarantee stable optical transmission. According to the optimization, the problem of negative gain of the traditional BDF in the C + L wave band (especially 1524nm) is solved, the noise is reduced, and the practical value of broadband communication is improved.

The invention provides a low-noise single-frequency laser, which comprises a linear resonant cavity for realizing light field local constraint and gain amplification, and is characterized in that the linear resonant cavity comprises a gain optical fiber, an all-dielectric C-waveband narrow-band high-reflection metasurface structure and a miniature BIC high-Q-value metasurface structure; the first end of the gain optical fiber is welded and fixed with the all-dielectric C-waveband narrow-band high-reflection metasurface structure, and the second end of the gain optical fiber is welded and fixed with the miniature BIC high-Q-value metasurface structure; wherein the all-dielectric C-waveband narrow-band high-reflection metasurface structure is used for screening a C-waveband target wavelength through a narrow-band high-reflection characteristic and suppressing a non-target mode at the same time; the miniature BIC high-Q-value metasurface structure realizes a high-Q-value characteristic by suppressing radiation loss, so that the laser line width is efficiently compressed, and noise is suppressed. The low-noise single-frequency laser provided by the invention can finally realize low-noise and narrow-linewidth single-frequency laser output.

[Technical Problem] An optical modulator is provided that can suppress electrode loss at low frequencies below 50 GHz and suppress radiation loss at high frequencies above 50 GHz. [Solution] An optical modulator (1) includes a substrate (2) and at least one interaction portion (MZ) disposed on the substrate (2). The interaction portion (MZ) includes: first and second optical waveguides (10a, 10b) adjacent to each other formed on the substrate (2), and first and second signal electrodes (7a, 7b) disposed opposite the first and second optical waveguides (10a, 10b), respectively. No ground electrode is configured in a region (NZ) near the interaction portion (MZ), and a ground electrode is configured near at least one of an input portion and a terminal portion electrically connected to the first and second signal electrodes (7a, 7b).

The invention belongs to the technical field of optical microscopic imaging, and discloses a microscopic imaging system and a stimulated radiation loss microscope. The microscopic imaging system comprises an illumination mechanism used for providing a first light beam and a second light beam which are coaxially incident; the phase modulation optical device comprises multiple layers of diffractive optical elements, and the multiple layers of diffractive optical elements are arranged at intervals in the transmission direction of the first light beam and the second light beam and used for conducting phase modulation and convergence on the first light beam and the second light beam in a matched mode. And the first light beam and the second light beam can form a first light spot and a second light spot at the focal plane of the stimulated radiation loss microscope, and the first light spot and the second light spot are in one-to-one correspondence and coincide in center. According to the technical scheme of the invention, the stimulated radiation depletion microscope can be normally matched with a commercial laser which has a large bandwidth and wavelength drift and is used as an excitation beam and a depletion beam.

The application discloses an anti-interface rough scattering quantum cascade laser active region and a preparation method thereof. The application forms a topological interface state protected by chiral symmetry as a lasing upper energy level at the butt joint interface between a first superlattice region and a second superlattice region, the wave function of the topological interface state is strictly zero in the thick barrier center and the interface, thereby the non-radiation loss caused by the interface roughness scattering is inhibited from the root, and the upper energy level carrier lifetime is significantly prolonged. Based on this, the threshold current density of the quantum cascade laser is greatly reduced, and high-efficiency lasing of 10 μm wavelength can be realized at room temperature. Meanwhile, a mixed epitaxy process combining molecular beam epitaxy and metal organic chemical vapor deposition is adopted, the nanometer precision energy band design of the core active region is ensured, and the efficient growth of the thick film waveguide layer is realized, which is beneficial to the practicalization and large-scale preparation of the device.

The invention belongs to the technical field of microwave communication, and particularly discloses a low-loss differential transmission line structure based on a common dielectric layer. According to the invention, the technical means of alternately laminating multiple transmission layers and dielectric layers and arranging through holes for vertical interconnection is adopted, so that an electromagnetic field is distributed in the air above and below the conductor as much as possible, and the side surface of the signal transmission conductor is grooved, so that the dielectric loss of the substrate is directly reduced; signal transmission conductors are connected through high-density metalized through holes, so that signal current can flow in parallel in a plurality of metal layers through the through holes, the equivalent cross sectional area of current circulation is remarkably increased under the high-frequency skin effect, the equivalent resistivity is reduced, and the conductor loss is reduced; meanwhile, the grounding conductors are connected in parallel through the through holes, an electromagnetic field is bound around the signal transmission conductor, and radiation loss and mutual interference are restrained to the maximum extent. Compared with the prior art, the effects of greatly reducing high-frequency loss and improving signal integrity on a common dielectric layer are achieved.

The metasurface resonator comprises a plurality of unit structures arranged periodically, each unit structure comprises a substrate layer and an L-shaped metal column, the L-shaped metal column is arranged at the center of the upper surface of the substrate layer, and the L-shaped metal column is arranged at the center of the upper surface of the substrate layer. The L-shaped metal column is composed of two cuboid metal columns which are perpendicular to each other, and the heights of the two cuboid metal columns which are perpendicular to each other are adjusted through a height scaling factor. By adjusting the height scaling factor of the metasurface resonator, the dissipation characteristic of the resonance mode supported by the metasurface resonator can be controlled, when the height scaling factor is reduced, the local state of the high-loss and low-quality factor supported in the metasurface resonator is evolved into the non-local state of the low-loss and high-quality factor, and the local state of the high-loss and low-quality factor is changed into the non-local state of the low-loss and high-quality factor. And non-local plasmon resonance with smaller radiation loss, narrower line width and higher quality factor is excited. By using the non-local plasmon resonance of the high-quality factor, the GH displacement can be greatly enhanced.

The invention provides a luminous copper halide cluster as well as a preparation method and application thereof. The light-emitting copper halide cluster has visible light emission with high light-emitting efficiency in a film state, the molecular structure of the light-emitting copper halide cluster is high in expansibility, and the light color is easy to regulate and control. Meanwhile, the copper halide cluster is good in machinability, and a membrane can be prepared through a vacuum sublimation method or a solution method. The two problems of the majority of copper halide cluster luminescent materials in the prior art are overcome: (1) the copper halide cluster luminescent materials are poor in processability, difficult to sublimate and low in solubility; and (2) the non-radiation loss of the excited state is serious, resulting in insufficient luminous efficiency of the film.

The present invention provides a transition structure from a radio frequency chip to a substrate integrated waveguide, the transition structure comprising: a substrate integrated waveguide and a radio frequency chip. The substrate integrated waveguide comprises a substrate, a first through hole, a second through hole, and a coupling structure, wherein the second through hole is the grounding end of the substrate integrated waveguide; the coupling structure is located between two rows of first through holes; and the radio frequency chip is located above the coupling structure. During the application of the transition structure, the radio frequency signal of the radio frequency chip enters the substrate integrated waveguide, the coupling structure changes the surface current to excite multi-mode resonance, and couples the radio frequency signal to the substrate integrated waveguide in the form of an electromagnetic wave. Since the second through hole is grounded, the electromagnetic wave is impedance matched through the second through hole during transmission along the arrangement direction of the first through holes. The present invention provides a transition structure with broadband and low loss characteristics through the coordination between the coupling structure, the first through hole, and the second through hole, and does not provide a microstrip line, thereby avoiding radiation loss.

The utility model discloses a strip line feed-in directly modulated laser, which comprises two parallel ceramic circuit boards, a ceramic dielectric layer is clamped between the two groups of ceramic circuit boards, the ceramic circuit boards and the ceramic dielectric layer form a microstrip line, and a metal layer is arranged on the inner surface of each ceramic circuit board to form a closed radio frequency transmission line. The ceramic dielectric layer is clamped between the two parallel ceramic circuit boards to form the closed microstrip line structure, and the laser chip is embedded in the microstrip line, so that direct feed-in of radio frequency signals is realized, gold wire connection is not needed, parasitic parameter influence caused by gold wires is eliminated fundamentally, and the service life of the laser is prolonged. The microstrip line is designed in a closed mode, electromagnetic waves are effectively prevented from being diffused to the surrounding space, radiation loss in the signal transmission process is reduced, meanwhile, the crosstalk risk between adjacent circuits is reduced, and the overall performance and reliability of a system are improved.

The invention relates to the technical field of luminescent material synthesis. The invention provides a Te-based hybrid halide luminescent material and a preparation method thereof. The luminescent material is of a zero-dimensional organic-inorganic hybrid crystal structure and comprises [TeCl6] < 2-> anions and organic phosphonium cations (C25H21PCl) < + > containing polar substituent groups. The preparation method comprises the following steps: dissolving tellurium dioxide in hydrochloric acid; continuously adding (2-chlorobenzyl) triphenyl phosphonium chloride, and reacting to generate a precipitate; centrifugally separating the precipitate, and drying under a vacuum condition to obtain intermediate powder; dissolving the powder in acetonitrile; and putting the solution into a sample bottle, putting the sample bottle into a sealed container containing diethyl ether, and carrying out solvent diffusion crystallization to obtain the luminescent material. According to the luminescent material, energy coupling and non-radiation loss between luminescent units are reduced, excitation energy can be more sufficiently converted into radiation luminescence, the luminous efficiency is improved, the luminescent material can be better matched with a blue light wave band, and the luminescent material is suitable for application scenes such as high-brightness solid-state illumination and photoelectric display.

An arc chamber that includes one or more components that include a low thermal conductivity region is disclosed. The low thermal conductivity region may be formed using additive manufacturing to create a lattice pattern, stochastic infill, or hollow void. The low thermal conductivity regions are used to direct the flow of heat to desired areas, such as the faceplate of the arc chamber. The lattice pattern may be located within the end plates of the arc chamber, such that the heat from the cathode and repeller are directed toward the faceplate and away from the bottom of the arc chamber. The lattice pattern may also be located in the side walls and the bottom wall to reduce the amount of heat that is lost to the environment through conduction and radiation.

The utility model provides a heat preservation inflatable mattress provided with silver films, the heat preservation inflatable mattress provided with the silver films comprises a mattress outer layer film, three layers of silver films and two layers of protective films are arranged in the mattress outer layer film, and a layer of protective film is arranged between two adjacent layers of silver films. According to the heat preservation inflatable mattress with the silver films, the three layers of silver films are arranged to form multiple reflection barriers, heat radiation loss is effectively blocked, the protective films serve as spacing layers, the positions of the silver films are fixed, the pressure resistance of the mattress is enhanced through the high elasticity of the protective films, and deformation after inflation is prevented. Through the alternative stacking design of the silver films and the protective films, the specific hole layout and the welding point structure, the heat reflection path is optimized, the interlayer binding force is enhanced, light weight and durability are balanced, the heat preservation performance is remarkably improved, and the service life is remarkably prolonged.

The invention relates to the technical field of wireless communication, in particular to a liquid crystal phase shifter and a liquid crystal antenna. The liquid crystal phase shifter comprises a liquid crystal box and a radio frequency substrate, the liquid crystal box comprises a first substrate and a second substrate which are oppositely arranged, a liquid crystal layer located between the first substrate and the second substrate, a first microstrip line and a first metal layer, the first microstrip line is located on the side, facing the second substrate, of the first substrate, the first metal layer is located on the side, facing the first substrate, of the second substrate, and the first metal layer is grounded; the radio frequency substrate comprises a third substrate and a second microstrip line located on one side of the third substrate. And the first microstrip line is electrically connected with the second microstrip line through the connecting structure. According to the invention, radiation loss and unexpected radiation can be reduced, and the accuracy and power of signal transmission can be improved.

The invention provides an electro-optical modulator based on a slit type silicon-lithium niobate thin film. The electro-optical modulator comprises a substrate, a lithium niobate film layer, a waveguide structure layer, a first metal electrode layer, a second metal electrode layer, a wrapping layer and a high dielectric constant layer. According to the invention, the high-refractive-index material is used for clamping the slit-type waveguide of the low-refractive-index material, so that the constraint effect on a light field is enhanced; through the design of the two functional covering layers, the silicon dioxide covering layer located on the waveguide structure layer is firstly designed, leakage of an optical mode field is reduced, radiation loss is reduced, and through optimization of structure parameters such as the too narrow distance between the first metal electrode layer and the second metal electrode layer and proper widening of the distance, the optical mode field can be effectively improved. The absorption loss of the metal electrode to the waveguide is reduced again; and secondly, through the design of the high dielectric constant layer at the top, the electric field intensity of the waveguide center is greatly enhanced, the problem that the modulation efficiency and the loss need to be balanced is solved, and the purpose of considering both low loss and high efficiency is finally achieved.

To provide a laminate for optical waveguides that excels in reducing radiation loss, heat resistance, and low birefringence. [Solution] A laminate for optical waveguide having a core layer and a cladding layer, wherein the core layer is made of a first polyimide having structural units represented by the following general formula (1), and the cladding layer is made of a second polyimide having structural units represented by the following general formula (1), and the fluorine substitution rate of the first polyimide is f core The fluorine substitution rate of the second polyimide is set to f. clad When this is the case, the following equation: f clad >f core This is a laminate for optical waveguides that satisfies the following conditions. JPEG2026073954000035.jpg50169

The invention belongs to the technical field of optical microscopic imaging, and discloses a microscopic imaging system and a stimulated radiation loss microscope. The microscopic imaging system comprises an illumination mechanism used for providing a first light beam and a second light beam which are coaxially incident; the annular partition phase modulation element comprises a first phase modulation area and a second phase modulation area connected to the peripheral side of the first phase modulation area, the first phase modulation area is circular, and the second phase modulation area is annular; the first phase modulation area and the second phase modulation area are configured to perform phase modulation and convergence on a first light beam and a second light beam which are vertically incident respectively, so that a first light spot and a second light spot which are in one-to-one correspondence and coincide in center are formed on the focal plane of the stimulated radiation loss microscope respectively. According to the technical scheme, light energy loss caused when the microscope adopts a high-numerical-aperture illumination objective lens is improved, miniaturization of the system is facilitated, and the imaging quality is improved.

The invention provides a low-cost and high-performance hybrid integrated coaxial line directional coupler and a radio frequency module. A hybrid integration scheme of the single-layer double-sided printed circuit board and the metal cavity is adopted, so that the number and cost of assembly accessories are greatly reduced. Meanwhile, the single-layer double-sided printed circuit board is matched with the metal cavity to form an effect similar to a coaxial coupling line, radiation loss is effectively inhibited, field distribution is improved, and therefore the insertion loss, the coupling flatness and the isolation performance of the coupler are improved. Part of medium in the middle of the transmission line on the circuit board is hollowed out, phase compensation is carried out on transmission signals of the coupling line, and the excellent performance of the directional coupler in the aspects of coupling degree, return loss, insertion loss and isolation is further achieved. Under the condition of ensuring the performance of the device, the medium between the transmission line and the ground is reserved, and the physical stability of the device is improved.

An optical arrangement includes an optical printed circuit board (OPCB) having at least a first optical waveguide having a first end located on the OPCB. The optical arrangement also includes at least one photonic integrated circuit (PIC) mounted to the OPCB. The PIC includes a second optical waveguide. The first waveguide has a second end located on a portion of the second waveguide to optically couple light between the PIC and the first waveguide. The portion of the second waveguide on which the second end of the first waveguide is located has an inverse taper. The inverse tapered portion is defined by a plurality of segments. The segments of the inverse tapered portion each have a length and a taper rate that causes each segment to make an equal contribution to any radiation losses in the mode transformation of light being coupled between the first and second waveguides.

The invention discloses a terahertz pure silicon equiphase low-loss waveguide based on a bound state in a continuous spectrum, and belongs to the technical field of terahertz on-chip communication. The waveguide comprises a conical gradual change input structure, a first straight waveguide, an equiphase waveguide, a second straight waveguide and a conical gradual change output structure which are sequentially connected along a transmission direction, the equiphase waveguide is of a one-dimensional photonic crystal structure formed by arranging a plurality of periodic unit structures, each unit is a cuboid made of a high-resistance silicon material, and symmetrical elliptic cylindrical grooves are formed in the upper surface and the lower surface of each unit. Energy band degeneracy of monopole and dipole modes is realized through points in a Brillouin region, a Dirac cone is formed, a near-zero effective refractive index is obtained at a central working frequency, and equiphase transmission is realized; and meanwhile, a bound state mechanism in a continuous spectrum is utilized to greatly improve quality factors and suppress radiation loss. The waveguide supports flexible adjustment of the working frequency through geometric dimension equal-proportion scaling, covers the frequency band of 0.1-10 THz, and can be designed to be of a bent structure. According to the invention, an all-silicon process is adopted, the structure is compact, the loss is low, and the device is suitable for high-fidelity signal transmission and processing in a terahertz integrated system.

The asphalt heat preservation tank comprises a tank body, and a first reflecting layer, a heat preservation layer and a second reflecting layer which are sequentially arranged from inside to outside. The device is characterized in that a static air layer is formed at the interval of 40-60mm between the first reflecting layer and the tank body, and dry air is filled to block conduction and convection heat dissipation; the first reflecting layer adopts composite aluminum foil and reflects radiant heat of the tank body back to the tank body; the thermal insulation layer is made of high-density rock wool; the second reflecting layer is a galvanized steel sheet, and the inner galvanized layer secondarily reflects residual heat. Through the synergistic effect of the static air layer, the double-reflection layer and the heat preservation layer, a radiation-conduction-convection triple heat inhibition mechanism is formed, and the problem that the energy consumption of the asphalt storage tank is high due to large heat radiation loss and low heat preservation efficiency is solved.

The invention discloses a design method of a waveguide-microstrip hybrid integrated low-cost low-insertion-loss differential transmission line, and belongs to the technical field of low-insertion-loss board-level signal transmission. The waveguide-microstrip hybrid integrated low-cost low-insertion-loss differential transmission line comprises a dielectric substrate, a transmission assembly is arranged on the dielectric substrate, coplanar metal grounds are arranged on the two sides of the transmission assembly, first metal through holes are formed in the coplanar metal grounds, and a second metal through hole is formed in the coplanar metal grounds; the transmission assembly is provided with a second metal through hole. By adopting the design method of the waveguide-microstrip hybrid integrated low-cost low-insertion-loss differential transmission line, the transmission loss is remarkably reduced, natural impedance matching is realized in a wide frequency band, and the common-mode rejection ratio is improved; the PCB is completely compatible with a traditional PCB in process, a low-cost substrate is adopted, and the material cost is reduced; an electromagnetic field is restrained through the metal through hole array, radiation loss is reduced, the crosstalk rejection ratio is improved, meanwhile, heat dissipation and breakdown characteristics are optimized through the air through holes, the power capacity is improved, and a low-loss, low-cost and high-reliability transmission solution is provided for scenes such as high-frequency communication and high-speed interconnection.

The invention discloses a square SIW (substrate integrated waveguide) cavity and strip line resonator mixed miniaturized filter, which comprises a dielectric layer, the top metal layer is located on the upper surface of the dielectric layer; the middle metal layer is located in the middle of the dielectric layer; the bottom metal layer is located on the lower surface of the dielectric layer; the metalized through hole array penetrates through the dielectric layer and is connected with the top metal layer and the bottom metal layer; the first metalized blind hole and the second metalized blind hole are used for connecting the middle metal layer and the bottom metal layer; the first metalized through hole and the second metalized through hole are connected with the top metal layer and the bottom metal layer; a feed microstrip line; the strip line resonator is embedded in the SIW cavity, the hybrid structure introduces an additional transmission zero point for the filter while reducing the size of the filter and reducing radiation loss, and the stop band frequency selection characteristic of the filter is improved.

The application discloses a high-quality-factor hybrid metal-dielectric plasmonic resonant optical filter; the filter comprises a substrate layer, a high-refractive-index dielectric layer, a low-refractive-index dielectric layer and a metal grating layer which are sequentially stacked upwards; the substrate layer is made of a low-refractive-index transparent dielectric material; the material of the high-refractive-index dielectric layer has a refractive index greater than the refractive index of the material of the low-refractive-index dielectric layer and the substrate material; the metal grating layer is provided with a grating structure with periodic arrangement and comprises three metal strips in one device period; the width of the middle metal strip is greater than the width of the two metal strips on the sides; the radiation loss of the coupling mode is adjusted by adjusting the width of the middle metal strip, and then the quality factor of the filter is adjusted. The application has the advantages of simple structure, high quality factor, compatibility with traditional integrated circuit preparation processes and the like, and has wide application in the fields of optical communication, hyperspectral and multispectral imaging and sensing and the like.

To provide a laminate for optical waveguides that excels in reducing radiation loss, heat resistance, and low birefringence. [Solution] A laminate for optical waveguide having a core layer and a cladding layer, wherein the core layer is made of a first polyimide having structural units represented by the following general formula (1), and the cladding layer is made of a second polyimide having structural units represented by the following general formula (1), and the fluorine substitution rate of the first polyimide is f core The fluorine substitution rate of the second polyimide is set to f. clad When this is the case, the following equation: f clad >f core This is a laminate for optical waveguides that satisfies the following conditions. JPEG0007849634000035.jpg50169