阅读说明：本技术 一种可传输高功率中红外激光的单模硫系玻璃微结构光纤 (Single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser ) 是由 杨志勇 李跃兵 冯宪 任和 祁思胜 于 2021-08-10 设计创作，主要内容包括：一种可传输高功率中红外激光的单模硫系玻璃微结构光纤,包括基底材料和填充材料,填充材料为若干个镶嵌于基底材料内部的呈多层周期性排列的填充柱,最内层填充材料围绕的区域为光纤的纤芯,填充材料与基底材料共同构成的呈多层周期性排列的结构形成光纤的包层,填充柱的直径d与相邻两个填充柱中心间距??的比值d/??为0.30～0.45,基底材料为Ge-Sb-S硫系玻璃；填充材料为Ge-As-S硫系玻璃；基底材料的折射率大于填充材料的折射率；光纤端面镀有ZnS和Al-(2)O-(3)交替叠加的若干层增透膜。本发明光纤具有超大模场和高抗损增透膜,且所选化学组成的光纤材料具有较高的激光损伤阈值,能够传输百瓦级平均功率的中红外激光。(A single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser comprises a base material and a filling material, wherein the filling material is a plurality of filling columns which are embedded in the base material and are arranged in a multi-layer periodic mode, an area surrounded by the filling material at the innermost layer is a fiber core of the optical fiber, the filling material and the base material jointly form a multi-layer periodic-arrangement structure to form a cladding of the optical fiber, the ratio d/Ʌ of the diameter d of each filling column to the center distance Ʌ of two adjacent filling columns is 0.30-0.45, and the base material is Ge-Sb-S chalcogenide glass; the filling material is Ge-As-S chalcogenide glass; the refractive index of the substrate material is greater than that of the filling material; ZnS and Al plating on optical fiber end face 2 O 3 Several layers of antireflection films are alternately stacked. The optical fiber has an ultra-large mode field and a high-loss-resistant antireflection film, and the optical fiber material with the selected chemical composition has a higher laser damage threshold value and can transmit mid-infrared laser with hundred watt-level average power.)

1. A single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser is characterized in that: the optical fiber filling material comprises a substrate material and a filling material, wherein the filling material is a plurality of filling columns which are embedded in the substrate material and are arranged in a multi-layer periodic manner and are surrounded along the center line of the substrate material, the area surrounded by the innermost filling material is a fiber core of the optical fiber, the filling material and the substrate material jointly form a multi-layer periodic arrangement structure to form a cladding of the optical fiber, the ratio d/Ʌ of the diameter d of each filling column to the center distance Ʌ of two adjacent filling columns is 0.30-0.45, the substrate material is Ge-Sb-S chalcogenide glass, and the chemical formula of the Ge-Sb-S chalcogenide glass is Ge_xSb_yS_(1-x-y)Wherein x = 0.15-0.25, y = 0.1-0.2; the filling material is Ge-As-S chalcogenide glass with the chemical formula of Ge_mAs_nS_(1-m-n)Wherein m = 0.15-0.26, n = 0.08-0.25; the refractive index of the substrate material is greater than that of the filling material; ZnS and Al plating on optical fiber end face₂O₃Several layers of antireflection films are alternately stacked.

2. The single-mode chalcogenide glass microstructured optical fiber capable of transmitting high-power mid-infrared laser according to claim 1, wherein the number of the multiple layers in the multiple layer periodic arrangement is at least two, and each layer of the packed columns is in a regular hexagonal arrangement.

3. The single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser according to claim 1, wherein a core diameter of the optical fiber is larger than or equal to 150 μm.

Technical Field

The invention belongs to the technical field of glass optical fibers, and particularly relates to a single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser.

Background

The mid-infrared band of 2-5 microns contains fundamental frequency vibration frequencies of a large number of molecules, the vibration absorption cross sections of the molecules are large, and the wavelength and spectral line form presents fingerprint characteristics; the interference of the 2-5 mu m mid-infrared laser by the fog and the smoke is small, and the long-distance transmission of several kilometers to dozens of kilometers can be realized; according to the Wien displacement law, the blackbody radiation peak wavelength of 2-5 mu m corresponding to the temperature of 200-700 ℃ is close to the combustion temperature of a common engine, the blackbody radiation peak wavelength is a main detection waveband for infrared search and tracking, and the directional pressing type infrared interference by adopting hectowatt-level high-power laser in the same waveband is the most direct and effective means for resisting infrared tracking. Therefore, the 2-5 mu m intermediate infrared laser technology has important application in the fields of atmospheric remote sensing, satellite-ground communication, medical health, environmental protection monitoring, national defense safety and the like.

The optical fiber has the advantages of high output beam quality, low unit length cost, flexibility, compact structure, light weight, high portability and the like, and the low-loss quartz glass optical fiber technology plays a key role in the development process of a kilowatt-to-kilowatt-level high-power optical fiber laser technology with a near-infrared wave band of 1-2 mu m. The current rapidly developing mid-infrared laser technology has also shown a trend towards tight integration with fiber optic technology. For example, a mid-infrared fiber laser and a mid-infrared fiber supercontinuum light source both have to use a fiber medium; in the wavelength band above 3 μm, mid-infrared quantum cascade lasers based on semiconductor material technology have also begun to give up the clumsy way of free-space output, and instead adopt more flexible fiber-coupled output technology. Therefore, the rapid development of mid-infrared high-power laser technology urgently requires that mid-infrared fiber technology follow up rapidly.

The mid-infrared optical fiber includes two types of glass optical fibers including tellurite glass optical fibers of non-quartz glass, fluoride glass optical fibers and chalcogenide glass optical fibers, and crystal optical fibers, and the latter is represented by halide crystal optical fibers. Different from crystals, at high temperature, parameters such as viscosity of glass and the like continuously change along with temperature, and a fiber type optical waveguide with continuous length of kilometers or more can be drawn from a prefabricated rod, although the cost of a special glass optical fiber in the preparation of high-purity glass and the preparation of the optical fiber is very high, once the special glass optical fiber is produced in mass, the cost of unit length can be greatly reduced; in addition, glass fibers can be directly fabricated into single mode waveguides. Therefore, glass fibers have absolute advantages over crystal fibers in terms of manufacturing cost and output beam quality.

Among the mid-infrared glasses, chalcogenide glasses based on chalcogen elements (sulfur, selenium, tellurium) are optical fiber materials capable of covering the widest wavelength band of mid-infrared 2 μm or more. In addition, the third-order Kerr nonlinear index of refraction n of chalcogenide glass₂At 10^-18~10^-17m²the/W magnitude is the highest of all optical glass and is 2-3 magnitude higher than that of quartz glass; the peak laser power required to produce the same nonlinear phase shift in chalcogenide fibers is 2-3 orders of magnitude lower than that of silica fibers with the same core diameter. Therefore, the three most important applications of chalcogenide glass fibers are high-power mid-infrared laser transmission, mid-infrared nonlinear frequency generation (such as stimulated raman scattering, stimulated brillouin scattering, and mid-infrared supercontinuum generation), and mid-infrared fiber bundle thermographic transmission. Both of which require that the fiber be able to withstand and output relatively high laser powers.

At present, the power level of near-single-mode continuous output of the mid-infrared laser on a wave band of 2-5 mu m reaches hundreds of watts. The requirement of the mid-infrared optical fiber transmission technology is urgently needed, and the mid-infrared optical fiber transmission technology can bear hectowatt-level high-power mid-infrared laser while meeting the requirement of near single-mode output. In addition, the application requirements of laser remote sensing, photoelectric countermeasure and the like are that the intermediate infrared 2-5 mu m optical fiber super-continuum spectrum light source has a flat spectral line and a high spectral power density. Specifically, the power density of the useful 2-5 μm band spectrum is required to reach 10-100 mW/nm, i.e. the total average power of the spectrum is 30-300W. Considering the factors of pump coupling efficiency, fiber loss, light-light conversion efficiency generated by pump-supercontinuum and the like, the single-mode output chalcogenide fiber is required to bear hundred watt-level intermediate infrared ultrafast pulse laser pumping. However, the maximum average power that can be borne by the currently reported single-mode chalcogenide glass fiber is only 12W (@ 2 μm), and the fiber used is an As-S step-index fiber with a core diameter of 12 μm.

Disclosure of Invention

The technical problem to be solved is as follows: the invention provides a single-mode chalcogenide glass micro-structural optical fiber capable of transmitting high-power mid-infrared laser, aiming at the problem that the existing single-mode chalcogenide glass optical fiber is difficult to transmit the mid-infrared laser with high average power (dozens of watts to hundred watts), and the single-mode chalcogenide glass micro-structural optical fiber can transmit the mid-infrared laser with hundred watts of average power.

The technical scheme is as follows: a single-mode chalcogenide glass microstructure optical fiber capable of transmitting high-power mid-infrared laser comprises a base material and a filling material, wherein the filling material is a plurality of filling columns which are embedded in the base material and are arranged in a multi-layer periodic mode along the center line of the base material in a surrounding mode, the area surrounded by the filling material at the innermost layer is a fiber core of the optical fiber, the filling material and the base material jointly form a multi-layer periodic mode structure to form a cladding of the optical fiber, the ratio d/Ʌ of the diameter d of each filling column to the center distance Ʌ between every two adjacent filling columns is 0.30-0.45, the base material is Ge-Sb-S chalcogenide glass, and the chemical formula of the Ge-Sb-S chalcogenide glass is Ge_xSb_yS_(1-x-y)Wherein x = 0.15-0.25, y = 0.1-0.2; the filling material is Ge-As-S chalcogenide glass with the chemical formula of Ge_mAs_nS_(1-m-n)Wherein m = 0.15-0.26, n = 0.08-0.25; the refractive index of the substrate material is greater than that of the filling material; ZnS and Al plating on optical fiber end face₂O₃Several layers of antireflection films are alternately stacked.

Preferably, the number of the multiple layers in the multiple-layer periodic arrangement is at least two, each layer of packed columns is arranged in a regular hexagon, the innermost layer is a regular hexagon surrounded by 6 packed columns, and 6 packed columns are added for each additional layer from the innermost layer.

Preferably, the core diameter of the optical fiber is not less than 150 μm.

Has the advantages that:

(1) the mode field diameter of the single-mode chalcogenide glass microstructure optical fiber is more than 10 times larger than that of the traditional single-mode chalcogenide glass step index optical fiber, so that the middle infrared laser power which can be borne by the single-mode chalcogenide glass microstructure optical fiber is 1-2 orders of magnitude higher than that of the traditional single-mode chalcogenide glass step index optical fiber theoretically.

(2) The laser damage of the optical fiber usually occurs at the input end face, and the end face of the single-mode chalcogenide glass microstructure optical fiber of the invention is plated with a high-loss-resistant antireflection film (Al)₂O₃And the ZnS material has a laser damage resistance threshold far higher than that of chalcogenide glass), can effectively avoid the damage of the end face when high-power laser is incident, and obviously improve the laser power which can be born by the end face of the optical fiber.

(3) The substrate material (Ge-Sb-S) and the filling material (Ge-As-S) are both chalcogenide glass with high laser damage threshold, the laser damage threshold of the chalcogenide glass is more than 2 times higher than that of the traditional As-S chalcogenide glass material, and the laser power which can be born by the optical fiber can be effectively improved.

(4) The single-mode chalcogenide glass microstructure fiber can transmit mid-infrared laser with hundred watt-level average power, and is more than 10 times higher than the highest average power which can be transmitted by the currently reported single-mode chalcogenide glass fiber.

Drawings

FIG. 1 is a schematic cross-sectional view of a single-mode chalcogenide glass microstructured optical fiber according to the present invention.

The numerical designations in the drawings represent the following: 1-base material, 2-filler material.

Detailed Description

The invention is further described below with reference to the accompanying drawings and specific embodiments.

Example 1

Referring to FIG. 1, the substrate material 1 in this embodiment has a chemical formula of Ge_0.25Sb_0.1S_0.65Has a refractive index of 2.195 at a wavelength of 3 μm, and the filler 2 has a chemical formula of Ge_0.26As_0.08S_0.66The refractive index of the chalcogenide glass at the wavelength of 3 mu m is 2.122, the filling material 2 is embedded in the substrate material 1 and is surrounded along the central line of the substrate material 1 and is in two layers of filling columns which are periodically arranged, each layer of structure is in a regular hexagon shape, the innermost layer is in a regular hexagon shape which is surrounded by 6 filling columns, the region surrounded by the filling material at the innermost layer is a fiber core of the optical fiber, and the filling material and the substrate material are in contact with each otherThe materials together form a structure with multiple layers arranged periodically to form the cladding of the optical fiber. The diameter d of each packed column is 45 μm, the center-to-center distance Ʌ between two adjacent packed columns is 100 μm, d/Ʌ =0.45, and the diameter of the optical fiber core is 200 μm. ZnS and Al plating on optical fiber end face₂O₃And two layers of antireflection films are alternately superposed.

The specific process comprises the following steps: the Ge is prepared by combining the conventional vacuum melting-quenching technology with the glass distillation purification technology_0.25Sb_0.1S_0.65And Ge_0.26As_0.08S_0.66Glass, adopting conventional stacking and drawing technology to prepare microstructure optical fiber, adopting conventional electron beam evaporation technology to successively evaporate a ZnS film with the thickness of 242 nm and an Al film with the thickness of 325 nm on the end face of the optical fiber bundle₂O₃A film. The single-mode 2-micron continuous optical fiber laser with the highest average power of 400W (built in advanced laser material and device key laboratories of Jiangsu university) and the single-mode 4.6-micron quantum cascade laser with the average power of 300 mW (produced by Daylight Solutions company in the United states), CaF (fiber laser fiber field) in the prior art are adopted in a laboratory₂The transmission performance of the optical fiber was measured by a coupling lens, a power meter and a 2-16 μm beam quality analyzer (manufactured by DataRay corporation, usa), and the measurement results showed that: the optical fiber is in single-mode transmission at 2 mu m and 4.6 mu m, the transmission loss is 0.8 dB/m and 1.0 dB/m respectively, and the highest average power of 2 mu m laser which can be transmitted by the optical fiber is about 204W.

Example 2

In this embodiment, the substrate material has a chemical formula of Ge_0.15Sb_0.2S_0.65The chalcogenide glass has a refractive index of 2.361 at a wavelength of 3 μm, and the filler has a chemical formula of Ge_0.2As_0.18S_0.62The refractive index of the chalcogenide glass at the wavelength of 3 mu m is 2.236, the filling materials are filling columns which are embedded in the substrate material and are arranged periodically in three layers and surround along the central line of the substrate material, each layer of structure is a regular hexagon, the innermost layer is a regular hexagon (counted from inside to outside, the second layer is 12 filling columns, and the third layer is 18 filling columns) surrounded by 6 filling columns, the area surrounded by the filling materials at the innermost layer is a fiber core of the optical fiber, and the filling materials and the substrate material jointly form a multilayer periodic structureThe linearly arranged structures form the cladding of the optical fiber. The diameter d of the packed column is 36 μm, the center-to-center spacing Ʌ of adjacent columns is 90 μm, d/Ʌ =0.40, and the fiber core diameter is 180 μm. The end face of the optical fiber is plated with Al₂O₃-ZnS-Al₂O₃And three layers of antireflection films are alternately superposed.

The specific process comprises the following steps: the Ge is prepared by combining the conventional vacuum melting-quenching technology with the glass distillation purification technology_0.15Sb_0.2S_0.65And Ge_0.2As_0.18S_0.62Glass, adopting conventional stacking and drawing technology to prepare microstructure optical fiber, adopting conventional electron beam evaporation technology to successively evaporate a layer of Al with the thickness of 210 nm on the end face of the optical fiber bundle₂O₃Film, a ZnS film with a thickness of 146 nm and an Al film with a thickness of 180 nm₂O₃A film. The single-mode 2-micron continuous optical fiber laser with the highest average power of 400W (built in advanced laser material and device key laboratories of Jiangsu university) and the single-mode 4.6-micron quantum cascade laser with the average power of 300 mW (produced by Daylight Solutions company in the United states), CaF (fiber laser fiber field) in the prior art are adopted in a laboratory₂The transmission performance of the optical fiber was measured by a coupling lens, a power meter and a 2-16 μm beam quality analyzer (manufactured by DataRay corporation, usa), and the measurement results showed that: the optical fiber is in single-mode transmission at 2 mu m and 4.6 mu m, the transmission loss is 0.6 dB/m and 0.8 dB/m respectively, and the highest average power of 2 mu m laser which can be transmitted by the optical fiber is about 178W.

Example 3

In this embodiment, the substrate material has a chemical formula of Ge_0.18Sb_0.18S_0.64Has a refractive index of 2.322 at a wavelength of 3 μm, and the filler has a chemical formula of Ge_0.15As_0.25S_0.6The chalcogenide glass has a refractive index of 2.264 at a wavelength of 3 mu m, the filling materials are four layers of filling columns which are embedded in the substrate material and are arranged periodically along the central line of the substrate material, each layer of structure is a regular hexagon, the innermost layer is a regular hexagon surrounded by 6 filling columns (counted from inside to outside, the second layer is 12 filling columns, the third layer is 18 filling columns, the fourth layer is 24 filling columns), and the region surrounded by the filling materials at the innermost layer is lightThe core of the fiber, the filling material and the substrate material form a structure which is formed by a plurality of layers and is arranged periodically to form the cladding of the optical fiber. The diameter d of the packed column is 22.5 μm, the center-to-center spacing Ʌ of adjacent columns is 75 μm, d/Ʌ =0.3, and the fiber core diameter is 150 μm. Optical fiber end face plated with ZnS-Al₂O₃-ZnS-Al₂O₃And four layers of antireflection films are alternately stacked.

The specific process comprises the following steps: the Ge is prepared by combining the conventional vacuum melting-quenching technology with the glass distillation purification technology_0.18Sb_0.18S_0.64And Ge_0.15As_0.25S_0.6Glass, adopting conventional stacking and drawing technology to prepare microstructure optical fiber, adopting conventional electron beam evaporation technology to successively evaporate a ZnS film with the thickness of 110 nm and an Al film with the thickness of 140 nm on the end face of the optical fiber bundle₂O₃Film, a ZnS film having a thickness of 90 nm and an Al film having a thickness of 120 nm₂O₃A film. The single-mode 2-micron continuous optical fiber laser with the highest average power of 400W (built in advanced laser material and device key laboratories of Jiangsu university) and the single-mode 4.6-micron quantum cascade laser with the average power of 300 mW (produced by Daylight Solutions company in the United states), CaF (fiber laser fiber field) in the prior art are adopted in a laboratory₂The transmission performance of the optical fiber was measured by a coupling lens, a power meter and a 2-16 μm beam quality analyzer (manufactured by DataRay corporation, usa), and the measurement results showed that: the optical fiber is in single-mode transmission at 2 μm and 4.6 μm, the transmission loss is 0.5 dB/m and 0.7 dB/m respectively, and the highest average power of 2 μm laser light which can be transmitted by the optical fiber is about 135W.

Comparative example 1

The optical fiber prepared by the comparative example is the same as the optical fiber prepared by the example 3, the only difference is that the two ends of the optical fiber are not coated with films, and the test result shows that: the optical fiber is in single-mode transmission at 2 mu m and 4.6 mu m, the transmission loss is 0.5 dB/m and 0.7 dB/m respectively, and the highest average power of 2 mu m laser which can be transmitted by the optical fiber is about 32W.

Comparative example 2

The difference from example 3 is that the substrate material in this comparative example has the chemical formula Ge_0.14Sb_0.09S_0.77Having a refractive index of 2 at a wavelength of 3 μm135, the fill material is of the formula Ge_0.14As_0.07S_0.79The refractive index of the chalcogenide glass of (2) at a wavelength of 3 μm is 2.068. The test result shows that: the optical fiber is in single-mode transmission at 2 mu m and 4.6 mu m, the transmission loss is 1.5 dB/m and 1.8 dB/m respectively, and the highest average power of 2 mu m laser which can be transmitted by the optical fiber is about 36W.