32results about How to "Reduce the attenuation factor" patented technology

The invention relates to a low-attenuation bending insensitive single-mode optical fiber for an optical communication transmission system. The optical fiber comprises a core layer and a cladding layer. The optical fiber is characterized in that the refractive index of the core layer is distributed according to an alpha-order parabola, and the distribution index alpha is 1.5-9.0; the cladding layer is sequentially formed by an inner cladding layer, an intermediate cladding layer and an outer cladding layer from inside to outside; the maximal refractive index difference delta 1 of the parabola core layer is 0.25-0.45 percent, and the radius R1 of the core layer is 5.0-7.0mu u; the relative refractive index different delta 2 of the inner cladding layer is -0.20-0 percent, and the radius R2 of the inner cladding layer is 7.0-10.0mu m; the relative refractive index difference delta 3 of the intermediate cladding layer is -0.20-0 percent, and the radius R3 of the intermediate cladding layer is 10.0-20.0mu m; and the outer cladding layer is a pure quartz glass layer. The low-attenuation bending insensitive single-mode optical fiber has reasonable refractive index section design and low doping amount, and has excellent attenuation resistance and bending resistance.

The invention relates to a single-mode optical fiber with ultralow attenuation and a large effective area. The single-mode optical fiber comprises a core layer and a wrapping layer and is characterized in that the core layer comprises a sinking core layer body and an outer core layer body from center to outside; the wrapping layer comprises an inner wrapping layer body, a sinking inner wrapping layer body, an auxiliary outer wrapping layer body and an outer wrapping layer body from inside to outside; the radius R1 of the sinking core layer body ranges from 1.5 Mum to 4 Mum, and the relative refractivity ranges from minus 0.10% to 0.02%; the radius R2 of the outer core layer body ranges from 4.5 Mum to 6.5 Mum, and the relative refractivity ranges from minus 0.08% to 0.10%; the radius R3 of the inner wrapping layer body ranges from 9 Mum to 15 Mum, and the relative refractivity ranges from minus 0.25% to minus 0.1%; the radius R4 of the sinking inner wrapping layer body ranges from 12 Mum to 20 Mum, and the relative refractivity ranges from minus 0.6% to minus 0.25%; the radius R5 of the auxiliary inner wrapping layer body ranges from 35 Mum to 50 Mum, and the relative refractivity ranges from minus 0.45% to minus 0.15%; the outer wrapping layer body is a pure silicon dioxide glass layer. The single-mode optical fiber has the large effective area and good bending loss and chromatic dispersion performance, the cabling cutoff wavelength is smaller than 1530 nm, and the production cost is low.

The invention relates to optical fiber heat treatment method and device. In the method, a maintaining furnace for thrilling the optical fibers is set to perform temperature-preservation heat treatment on optical fibers which are drawn from a fiber drawing furnace and in a high temperature and uncooled state; the temperatures of the optical fibers entering and removing from the maintaining furnace are respectively controlled to be 1400 DEG C-1800 DEG C and 1145 DEG C-1170 DEG C; the optical fibers thrill through the maintaining furnace for 0.08s-0.24s; and the temperature of the chamber of the maintaining furnace is controlled between 600 DEG C and 1300 DEG C. The maintaining furnace has a heat preservation effect on the cores of the optical fibers, the stay time of the optical fibers in an annealing temperature range is prolonged, the internal stress of the optical fibers is relieved, and the Rayleigh back scatter loss is reduced. The maintaining furnace has the advantages of simple structure and reliable performance; the inner chamber of the furnace is directly communicated with ambient air, which avoids the disturbance of protective gas in a drawing channel to the optical fibers, and thus, the stability of high-speed drawing is improved; and the equipment is simplified, and the cost is saved.

The invention discloses a stepped low-attenuation orbital angular momentum optical fiber. The stepped low-attenuation orbital angular momentum optical fiber comprises a core layer and a cladding layer, wherein the core layer has R1 of 3-5 microns and delta 1 of -0.08% to 0.08%; an annular core layer, a sunken cladding layer and an outer cladding layer sequentially coat the core layer from inside to outside; the annular core layer sequentially comprises an inner annular core layer, a sunken annular core layer and an outer annular core layer from inside to outside; the inner annular core layer has R2 of 4-6 microns and delta 2 of 0.7%-1%; the sunken annular core layer has R3 of 5-7 microns and delta 3 of 0.6%-0.9%; the outer annular core layer has R4 of 7-9 microns and delta 4 of 0.7%-1%, and delta 4 is equal to or basically equal to delta 2; the sunken cladding layer has R5 of 11-16 microns and delta 5 of -0.6% to -0.3%; the relative refractive index difference is a relative refractiveindex difference between each layer of the optical fiber and the outer cladding layer; and the outer cladding layer is an outer cladding layer with a negative refractive index relative to a pure silicon dioxide layer. According to the stepped low-attenuation orbital angular momentum optical fiber, the long-distance signal transmission of four mode groups can be supported; the attenuation is low; and the comprehensive performance of the crosstalk of the optical fiber, the macro-bending and micro-bending loss of each mode, and the like is good.

The invention relates to a low-attenuation bend-insensitive single-mode optical fiber used in an optical communication transmission system, comprising a core layer, a sunken inner cladding, an inner cladding, a sunken outer cladding and a pure silica glass outer cladding, characterized in that The core layer is composed of the first core layer, the second core layer and the third core layer with the refractive index from high to low from the inside to the outside. The radius R1 of the first core layer is 2.5μm~3.3μm, and the relative refractive index The difference Δ1 is 0.25%~0.38%; the second core radius R2 is 4μm~5μm, and the relative refractive index difference Δ2 is 0.15%~0.25%; the third core radius R3 is 5.3μm~6.3μm , the relative refractive index difference Δ3 is -0.03%~0.15%. The core cladding of the present invention is related to the realization of low attenuation, large effective area, and better combination and unification of bending resistance. The optical fiber has an attenuation performance far superior to that of conventional G.652. The cost of building related base stations and other system equipment, and has better macroscopic bending performance than conventional G.652.D optical fiber, so as to meet the harsher wiring environment or FTTx use environment.

The present invention relates to a multi-core optical fiber and its branchable optical cable, comprising a common outer cladding and a plurality of fiber cores arranged in the common outer cladding, characterized in that the number of said fiber cores is eight, including a central fiber core and seven outer cores, the central core is arranged in the center of the common outer cladding, and the remaining seven cores are equidistantly distributed around the central core on the periphery of the central core, and the seven outer cores and The equal spacing d1 of the central core is 35-43 μm, the core spacing of the seven outer cores is 31-37 μm, and the eight cores are homogeneous single-mode optical fibers, and each core includes a core layer, a The inner cladding and the depressed cladding, and the common outer cladding are the outer cladding of each fiber core. The invention has a reasonable structure setting, not only low attenuation, small crosstalk between cores, and comprehensive performance such as macrobend loss of each channel is at a good level, but also can meet the transmission of C-band and O-band, while maintaining a high space division multiplexing dimension density while being compatible with existing devices.

The invention relates to a low attenuation gradient orbital angular momentum fiber. The low attenuation gradient orbital angular momentum fiber includes a core layer and a cladding layer; the core layer radius R1 is 3.5 [Mu]m to 5.5 [Mu]m, and the [Delta]1 is -0.08% to 0.08%; the core layer is covered by a ring core layer, a depressed cladding layer and an outer cladding layer; the ring core layerhas a gradual shape, and the top portion has a gradual concave shape, and is successively divided into an inner ring layer, a lower concave layer and an outer ring layer from the inside to the outside; the inner ring layer has a radius R2 of 4.5 [Mu]m to 6.5 [Mu]m and a [Delta]2 of 0.7% to 1%; the lower concave layer radius R3 is 8 [Mu]m to 13 [Mu]m, and the [Delta]3 is 0.6% to 0.9%; the outer ring layer has a radius R4 of 9[Mu]m to 15[Mu]m and a [Delta]4 of 0.7% to 1%; and the depressed cladding layer radius R5 is 11 [Mu]m to 16 [Mu]m, and the [Delta]5 is 0.6% to 0.3%; the relative refractive index difference is the relative refractive index difference between each layer of the fiber and the outer cladding layer; and the outer cladding layer is an outer cladding layer with a negative refractive index relative to a pure silicon dioxide layer. The low attenuation gradient orbital angular momentum fiber not only can support long-distance signal transmission with low attenuation of fourmode groups, but also has good comprehensive performances in crosstalk of the optical fiber, macro-bend and micro-bend loss of each mode and the like.

The invention relates to a single mode fiber with the lower manufacturing cost. The single mode fiber comprises a core layer, wherein a first inner wrapping layer, a second inner wrapping layer and an outer wrapping layer wrap the core layer in sequence. The single mode fiber is characterized in that the outer wrapping layer is made of natural siliceous sand, the absolute refraction index of the outer wrapping layer ranges from 1.4572 to 1.4574, the diameter alpha of the core layer is 8-10 micrometers, the refraction index difference delta n1 of the core layer and the outer wrapping layer ranges from 4.1*10<-3> to 6.4*10<-3>, the ratio b / a of the diameter b of the first inner wrapping layer to the diameter a of the core layer is greater than or equal to 1.6, the refraction index difference delta n2 of the first inner wrapping layer and the outer wrapping layer ranges from -2.4*10<-3> to -0.7*10<-3>, and the ratio c / a of the diameter c of the second inner wrapping layer to the diameter a of the core layer is greater than or equal to 3.6. The outer wrapping layer of an optical fiber prefabricated bar is made of the natural siliceous sand with the lower cost, so that the manufacturing cost of the optical fiber is lowered greatly; the structure of the inner wrapping layers and the outer wrapping layer is adopted, the ratio of the inner wrapping layers to the core layer is selected reasonably, and the fluorine mixing amount and the chloride ion concentration in the second inner wrapping layer are controlled, so that influence on optical attenuation from the impurities of the outer wrapping layer made of the natural siliceous land is reduced, and the water peak performance and the attenuation coefficient of the single mode fiber are reduced effectively.

The invention relates to a multi-core multi-mode optical fiber, comprising a plurality of core layers and a common outer cladding, characterized in that the number of the core layers is 2, 4 or 8, and each core layer is equally spaced along the circumferential direction , the spacing between adjacent core layers is 38-60 μm for 2 core layers, 38-48 μm for 4 or 8 core layers, and the inner cladding layer and the sunken cladding layer are sequentially coated from the inside to the outside of each core layer, forming a multi-core homogeneous and more Mode fiber, the core layer refractive index profile is parabolic, α is 1.9~2.1, core layer R1 is 12~20μm, core layer Δ1max is 0.7%~1.7%, inner cladding layer width is 0.5~2.5μm, Δ2 is ‑ 0.4%~0.0%, the unilateral width of the sunken cladding layer is 3~7μm, Δ3 is ‑0.7%~‑0.9%, and the common outer cladding is a pure silicon dioxide layer. The invention can not only support multi-mode transmission in the wavelength range of 850nm to 950nm and single-mode transmission in O-band / C-band, but also can optimize the optical fiber structure and viscosity matching to reduce attenuation, so that the crosstalk of the optical fiber, the macrobend and the microbend of each channel can be reduced. The comprehensive performance such as loss is at a good level.

The invention discloses a magnetic sensing composite material of an inorganic material layer and an amorphous soft magnetic core and a preparation method thereof. The magnetic sensing composite material comprises a soft magnetic core and a coating which is coated on the soft magnetic core; the soft magnetic core is prepared from the following components in percentage by weight: 4 to 6 percent of Si, 7 to 9 percent of Zr, 1 to 3 percent of Nd, 0.1 to 0.2 percent of Ce, 6 to 9 percent of B, 1 to 3 percent of Cr, 2 to 5 percent of Ni, 4 to 6 percent of Co and the balance of Fe; and the coating is prepared from TiO2, SiO2, MgO.Al2O3, Y2O3, ZrO2, NaO2 and sol, wherein the weight ratio of the TiO2, SiO2, MgO.Al2O3, Y2O3, ZrO2 and NaO2 to sol is 0.5:1:1:0.03:0.5:3.5 to 4:0.5 to 1. The prepared magnetic sensing composite material has low attenuation coefficient of magnetoelastic waves, low raw material cost, short production cycle and simple and convenient preparation process.

A single-mode optical fiber that has ultra-low loss and a large effective area and a preparation method therefor. The optical fiber has an inner core layer, a depressed core layer, an outer core layer, an inner cladding layer, a depressed cladding layer and an outer cladding layer that are arranged successively from the inside to the outside, wherein: the inner core layer, the depressed core layer, the outer core layer, the inner cladding layer, and the depressed cladding layer use silica as a base material and have a dopant added thereto, and the outer cladding layer is pure silica; and the relative refractive index of the inner core layer is Δn1, the relative refractive index of the depressed core layer is Δn2, the relative refractive index of the outer core layer is Δn3, the relative refractive index of the inner cladding layer is Δn4, the relative refractive index of the depressed cladding layer is Δn5, and the sizes of the relative refractive indices are: Δn1>Δn3>Δn2>Δn4>Δn5. The present optical fiber is prepared by using an MCVD process and an OVD process, and the effective area, cut-off wavelength, attenuation, dispersion, bending loss and other comprehensive properties thereof are good.

The invention relates to a low water peak and large-size optical fiber preform and a manufacturing method thereof. The manufacturing method is as follows: using an MCVD process to successively deposit an inner cladding layer and a core layer on the inner wall of a fluorine-doped quartz tube as a lower limit layer to obtain a deposition tube, and The deposition tube is melted and shrunk to obtain a solid prefabricated core rod with a core layer, an inner cladding layer and a sunken layer; the outer cladding loose body is deposited on the outside of the solid prefabricated core rod by the OVD process, and then sintered to obtain a composite core rod; the RIC process is used to The synthetic core rod and the continuous fused silica sleeve are combined to form a low water peak large-size optical fiber preform. The diameter of the optical fiber preform prepared by the present invention can reach 230mm, and the fiber drawing length of a single preform can reach 3300km. Attenuation coefficient ≤ 0.175dB / km.

Disclosed is a method for manufacturing an optical fiber preform based on a sleeve method, the method comprising the following steps: preparing an optical fiber mother core rod comprising a core layer and an inner cladding layer by using a VAD process, then heating and stretching the optical fiber mother core rod such that the curve degree of the stretched optical fiber core rod is less than 1 mm / m, then preparing a depressed layer by means of an OVD process, and finally, inserting the combined core rod into a quartz sleeve to form an optical fiber preform. The diameter of the prepared optical fiber preform may be up to 221 mm, the fiber pulling length of a single preform may be up to 2995 km, the attenuation coefficient of an optical fiber at a wavelength of 1310 nm is less than or equal to 0.305 dB / km, the attenuation coefficient of the optical fiber at a wavelength of 1383 nm is less than or equal to 0.275 dB / km, and the attenuation coefficient of the optical fiber at a wavelength of 1550 nm is less than or equal to 0.165 dB / km.