CN100345781C - Method for preparating special optical fiber - Google Patents
Method for preparating special optical fiber Download PDFInfo
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- CN100345781C CN100345781C CNB2005100493368A CN200510049336A CN100345781C CN 100345781 C CN100345781 C CN 100345781C CN B2005100493368 A CNB2005100493368 A CN B2005100493368A CN 200510049336 A CN200510049336 A CN 200510049336A CN 100345781 C CN100345781 C CN 100345781C
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01265—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt
- C03B37/01268—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt by casting
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/32—Eccentric core or cladding
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/34—Plural core other than bundles, e.g. double core
Abstract
The present invention discloses a method for preparing a special optical fiber. The present invention is characterized in that a cladding of a preform is divided into two symmetrical blocks to carry out pouring preparation respectively according to the geometric shape distribution of an optical fiber in a pouring hot melt connection method. Consequently, the preparation of an optical fiber preform comprises two steps: first, an initial glass block (a glass mother block) is poured and prepared according to a specific external shape; then, another complementary glass block (a bonding sub-block) is poured according to the requirement of the external shape; fusion welding is carried out to the mother block and the sub-block are when pouring the sub-block, wherein a mother body comprises part of cortical layer glass (in a half cylinder shape) and a doped optical fiber core rod, and a preform which can be drawn into an optical fiber can be obtained after carrying out thermal insulation and annealing. The special optical fiber can be obtained by common optical fiber drawing. The present invention has wider applicability, so that the present invention can not only be made into silicon fiber, but also be suitable for optical fibers of tellurate, phosphate, sulfide, etc. The present invention is easy to ensure that the obtained optical fiber accords with the requirements of original design.
Description
Technical field
The present invention relates to a kind of preparation method of optical fiber, especially relate to a kind of preparation method of special optical fiber.
Background technology
Research and development from existing optical fiber technology, conventional silica fibre has developed into very sophisticated degree as communication media, but in long-distance optical communication, still need set up many relayings amplifies, here produced the development need that is amplified to light amplification from electricity, especially the appearance of EDFA, advanced development of Photonic Network greatly, still along with the development of DWDM technology, the silicon matrix amplifying device can't satisfy the demand of its wide bandwidth and high gain amplifier, therefore various non-silica glass matrix optical fiber have been produced, as sulfide, tellurate, fluorochemical, the form of phosphoric acid salt or the like special optical fiber has obtained development fast in recent years.And in concrete optical transmission process, conventional fiber (multimode optical fibers or its cross section structure circle symmetry) can not be realized real single mode and stable polarization mode transmission, so many fibre systems (as optical fiber amplification, coherent fiber communication, fiber optic gyro, fibre optic interferometer) require special optical fiber, make transmission luminous energy remain on the single mode transport state or stable polarization mode of standard.Even the single-mode fiber of standard, in case any perturbation is arranged, the destruction that will cause single mode, and the change that produces polarization state, therefore, the optical fiber investigator has to intensify one's efforts, to seek better special optical fiber.
Preparing various special optical fibers has difficulty in various degree than preparation conventional (multimode or circle are symmetric) optical fiber on technology, the MCVD that the optical fiber investigators know (Modified Chemical Vapor Deposition) method is AT﹠amp; Breadboard Mc doctor Chesney of T BELL is invented; Britain University of Southampton utilizes part (gas phase fluorine) etch on the MCVD basis, success developed " knot " special optical fiber.In Japan, taked the technology approach of another preparation special optical fiber, it is the blank pipe that gets out two cylinder body shapes in the single mode prefabricated rods that VAD (vapor axial deposition) method is made along axis, and (its geometric position is symmetrical in the axle center) is adjacent to two stress rods then and imbeds blank pipe; Also very successful with such " panda " special optical fiber that this method makes.In Japan, another successful special optical fiber is (cylindrical) interior elliptical clad fiber, and its processing method is " subtracting compressed rod " technology of introducing on the basis of MCVD method, and without the partial corrosion technology.In the U.S., what healthy and free from worry (Corning) company used is again another kind of technology, its major technique is to insert plug in silica glass bushing pipe inside along axis, insert how much symmetric two stress rods on the plug both sides, and fill up glass stick in the blank parts of bushing pipe inside, can be used to stringy special optical fiber prefabricated rods thereby constitute.This processing method also is a kind of successful method, is called the optical fiber that healthy and free from worry technology (Corning Technique) wire drawing is come out, and its structural shape is similar to panda optic fibre (stressed zone is generally not really round, but does not influence the performance that it keeps polarization state).In the U.S., another attracting invention is AT﹠amp; The oval inner cladding optical fiber of the breadboard flat of T Bell, its major advantage are to be easy to determine orientations of major; The processing method for preparing this type optical fiber is that oval inner cladding prefabricated rods is flattened in the heating of the short-axis direction of ellipse, the prefabricated rods wire drawing at low temperatures of then this having been flattened.
One of existing technical problem of method of preparation " knot " optical fiber is a circularity that cannot say for sure to demonstrate,prove fibre core, this be because, in the rod motion that contracts since the stressed zone from both sides to the fuse stress application, and fuse is in hot melting state, so be easy to become elliptical shape in various degree.About the making of panda optic fibre, require primary single mode rod thicker, be beneficial to boring, have and use ultrasonic technique to hole, this kind technology implements accuracy requirement higher.About preparing similar panda optic fibre De Kangning technology, this technology mainly is the practiced processes difficulty, because plug and the stress rods position in sleeve pipe need keep sight alignment through whole drawing process, two stress rods need strict symmetry with respect to fibre core, the filling glass rod need be close to mutually, or the like.Above-mentioned several representational Technology, the rod that draws that wherein prepares tie fiber and the used prefabricated rods of oval inner cladding optical fiber is the solid glass rod, the prefabricated rods of panda optic fibre and healthy and free from worry casing fiber optic is drawn rod and is then needed to use hollow glass tube, and have venting hole on the tube wall, so that in the heating drawing process, discharge the bubble in the air gap between inner each binding face of prefabricated rods.
Close the problem of exhaust bubble about cold working, application number be propose in the Chinese invention patent of 94113945.X a kind of based on the direct stringy technology of mechanical cold working and folder rod, it is characterized in that used former be the symmetrical doped-glass cylinders of real several circles of material and structure thereof, geometrical shape according to special optical fiber is reprocessed these cylinders, thereby piece together the geometrical shape of required prefabricated rods, then with an end of this subassembly with draw excellent welding mutually, the other end is melt into cone shape, becomes fine for wire drawing.It adopts mechanical workout to determine physical dimension, and the space is discharged and filled up to the pressure that the cone that constantly diminishes when utilizing wire drawing is then shunk with bubble.Theoretically, this method can be processed the optical fiber of multiple distribution of shapes, but the processing of its glass cylinder because this method places one's entire reliance upon, therefore can't carry out the ideal optical fiber fabrication for brittle tellurate, chalcogenide glass etc., and with regard to cold glass, the specified shape surface working is exactly a problem that is difficult to guarantee precision.
Chinese patent application number 01128430.7 has been introduced a kind of manufacture method of preform, this invention using plasma chemical vapour deposition and two kinds of technologies of the outer vapour deposition of pipe are mixed the manufacturing preform, and comprise three steps: the plasma activated chemical vapour deposition method prepares plug; Manage outer vapour deposition process and prepare covering (being the base rod); The base rod is carried out sintering obtain prefabricated rods.This method can improve silicon optical fiber production efficiency, waveguiding structure easy to control.But it is effective that this method is primarily aimed at those silicon compound type optical fibers that can gasify, and other category of glass optical fiber can't realize that attainable optical fiber kind is few, and order device complexity.
Summary of the invention
Technical problem to be solved by this invention is the processing method that the preparation special optical fiber of a kind of novelty and practicality is provided at above-mentioned prior art present situation.
The present invention solves the problems of the technologies described above the technical scheme that is adopted: a kind of preparation method of special optical fiber, adopt the method for pouring caloric fusion, concrete processing step is as follows: 1. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add a cover in silicon carbon rod electric furnace and found, temperature of fusion is 850～950 ℃, obtains glass metal after fusing, stirring and clarification; 3. the temperature with glass metal drops to 800 ℃, is incubated 30 minutes; 4. glass metal is cast on the special-purpose excessively semicylinder casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2～5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the semicolumn glass stick; 5. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, then repeating step 2., 3., the glass metal that obtains is stand-by; 6. with the semicolumn glass stick and the combination of needed plug that obtain, be placed in the particular manufacturing craft, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature ± 5 ℃ of cladding glass; 7. particular manufacturing craft after the preheating is arranged to have 45 °～60 ° inclination angles, stand-by glass metal is taken out, pour in the particular manufacturing craft; 8. after particular manufacturing craft being put into fast the retort furnace that has been warming up to glass transformation temperature+5 ℃～glass transformation temperature+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2～5 ℃/hour speed, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the glass preform of single covering special optical fiber; 9. glass preform is carried out wire drawing on drawing wire machine, obtain single covering special optical fiber.
The plug of described step in 6. can be one, and this plug is arranged on the center of semicolumn glass stick, through step 6., 7., 8. and obtain single covering single-mode fiber 9..
The plug of described step in 6. can be one, and this plug is arranged on the center of departing from of semicolumn glass stick, through step 6., 7., 8. and obtain single covering spiral optical fiber 9..
The plug of described step in 6. also can be two, through step 6., 7., 8. and obtain single covering twin-core fiber 9..
Described plug can obtain with the following method: 1. according to the prescription requirement of glass of fiber core, choose raw material and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add a cover in silicon carbon rod electric furnace and found, temperature of fusion is 850～950 ℃, obtains glass metal after fusing, stirring and clarification; 3. reduce the temperature to 800 ℃, be incubated 30 minutes; 4. glass metal is cast on the casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2～5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the fibre core prefabricated rods; 5. take out this fibre core prefabricated rods, on drawing wire machine, carry out wire drawing, obtain plug through the polishing back.
Step 8. the back repeating step 1.～8., step 6. in the semicircle glass stick and the glass preform combination that obtain, be placed in the particular manufacturing craft, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature ± 5 ℃ of cladding glass; 7. particular manufacturing craft after the preheating is arranged to have 45 °～60 ° inclination angles, stand-by glass metal is taken out, pour in the particular manufacturing craft; 8. after particular manufacturing craft being put into fast the retort furnace that has been warming up to glass transformation temperature+5 ℃～glass transformation temperature+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2～5 ℃/hour speed, close the retort furnace power supply then, automatically be cooled to room temperature, repeatedly repeat, obtain the glass preform of many coverings special optical fiber.
Compared with prior art, the invention has the advantages that of the geometrical shape distribution of the processing method of this preparation special optical fiber according to optical fiber, its prefabricated rod cladding is divided into symmetric two pours into a mould making respectively, thereby the making of preform is divided into two steps, at first according to given configuration cast initial glass piece (being glass block), and then according to optical fiber profile cast other one of complementary (watering the zygote piece), when cast is fast, mother tuber and sub-piece are fused, wherein comprise the optical fiber cortex in the parent, and plug, behind insulation annealing, just can obtain to draw the prefabricated rods of optical fiber, carry out common drawing optical fibers and just can obtain special optical fiber.Compare with the various processing methodes of above-mentioned prior art, it both had been different from the MCVD method for preparing tie fiber and had added gas phase partial corrosion technology, the MCVD method that is different from the oval inner cladding optical fiber of preparation panda adds and subtracts the compressed rod technology, " the stress post embedment method " and " tiretube process " that are different from preparation panda optic fibre and healthy and free from worry polarization maintaining optical fibre, and " hot pressing prefabricated rods " method of preparation flat optical fiber, also be different from " geometric Process " that utilize glass cold working given configuration.
The advantage of the inventive method mainly contains three aspects, and the one, prepare special optical fiber with the inventive method, only need the little mould of cast of several specified shapes of design, carrying out the cast of glass matrix and molectron, and do not need other any special instrument; This casting mold can be with the form design of group cover because size is little, thereby can choose specific mould by desired, satisfies the diversity of special optical fiber physical dimension.The single-mode fiber of high core skin diameter ratio can not only be processed, and some symmetry or asymmetric special optical fibers can be processed.Make for plug in the parent piece, because its circle symmetry and composition unicity, so its easy-to-use casting+wire drawing, conventional MCVD method+wire drawing or other method make, the investigator who participated in optical fiber fabrication technology is familiar with, make the doped-glass column structure of circle symmetry or single component, much simpler and easy than non-round symmetrical structure, only need deposit, the rod that contracts (or cast), wire drawing.Carry out the amalgamation welding with parent and the complementary daughter glass that comprises multicomponent glass (part cladding glass and plug), just can obtain the geometrical body of special optical fiber prefabricated rods.Because special-purpose casting mold is arranged, the parent behind the location merges the preform that forms specified shape fully with regard to energy and daughter fully.The 2nd, this method is owing to adopt the pouring caloric fusion method to process, do not carry out mechanical workout or other processing technology, therefore can avoid the frangible danger of glass cold working, can not only be applicable to common silica glass, also be applicable to glass component optical fiber such as the big tellurate of fragility, sulfide.Because in fusion process, be fully according to gamma transition and softening temperature characteristic, the teeming temperature of calculating optimum and mold preheating temperature guarantee the clarification and the quick validity of bonded of glass.When glass heats up, because the heat affected zone volumetric expansion can as long as this stress does not surpass the maximum compressive strength σ c of glass, just can not influence the shape of glass and produce stress crack producing stress under compression on every side; During cooling, adopt horizontal temperature method and annealing technology, crackle eliminates stress; During fusion, utilize the colder firmware of high temperature melting of cast liquid, realize that best welding and minimum stress generate, thereby guarantee the feasibility of welding and the unchangeability of glass property.The 3rd, in cast, finish the fusion of glass.In order to guarantee the optical property of optical fiber, the core skin interface of prefabricated rods must keep tight rounding, and owing to be carry out interface when adopting cast fused, fused glass metal and remollescent mother glass group body carry out combination, owing to be at liquid internal, bubble can directly be discharged by pressure, thereby guarantees the clarification of glass casting body and the rounding seamlessness of interface.
Description of drawings
Fig. 1 is a hot pouring alloying process synoptic diagram of the present invention;
Fig. 2 prepares the particular manufacturing craft structural representation of single-mode fiber for the present invention;
Fig. 3 prepares the fused glass piece constitutional diagram of single-mode fiber for the present invention;
Fig. 4 prepares the process flow diagram of single-mode fiber for the present invention;
Fig. 5 prepares the process flow diagram of spiral optical fiber for the present invention;
Fig. 6 prepares the process flow diagram of twin-core fiber for the present invention.
Embodiment
Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.
Embodiment one: a kind of preparation method of special optical fiber, adopt the method for pouring caloric fusion, and concrete processing step is as follows: 1. use the material of tellurate as cladding glass, according to the prescription requirement of cladding glass, choose dusty raw materials and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add corundum and cover in silicon carbon rod electric furnace and found, temperature of fusion is 850 ℃, through fusing, stir and clarification back acquisition glass metal; 3. the temperature with glass metal drops to 800 ℃, is incubated 30 minutes; 4. glass metal is cast on the special-purpose semicylinder casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature Tg fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain semicolumn glass stick 1; 5. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, 2., 3. repeating step uses glass metal 3 stand-by the cast that obtains then; 6. with semicolumn glass stick 1 and plug 2 combinations of obtaining, plug 2 is arranged on the center of semicolumn glass stick 1, be placed in the particular manufacturing craft 4, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature Tg-5 a ℃ of cladding glass; 7. particular manufacturing craft after the preheating 4 is arranged to have 45 ° of inclination angles, stand-by cast is taken out with glass metal 3, pour in the particular manufacturing craft 4; 8. after particular manufacturing craft 4 being put into fast the retort furnace that has been warming up to glass transformation temperature Tg+5 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2 ℃/hour speed, close the retort furnace power supply then, be cooled to room temperature automatically, obtain the glass preform 5 of single covering single-mode fiber; 9. glass preform 5 is carried out wire drawing on drawing wire machine, obtain single covering single-mode fiber.
Embodiment two: a kind of preparation method of special optical fiber, adopt the method for pouring caloric fusion, and concrete processing step is as follows: 1. use the material of tellurate as cladding glass, according to the prescription requirement of cladding glass, choose dusty raw materials and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add quartz cover and found in silicon carbon rod electric furnace, temperature of fusion is 900 ℃, obtains glass metal after fusing, stirring and clarification; 3. the temperature with glass metal drops to 800 ℃, is incubated 30 minutes; 4. glass metal is cast on the special-purpose excessively semicylinder casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 3.5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain semicolumn glass stick 1; 5. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, 2., 3. repeating step uses glass metal 3 stand-by the cast that obtains then; 6. with semicolumn glass stick 1 and plug 2 combinations of obtaining, plug 2 is arranged on the center of departing from of semicolumn glass stick 1, be placed in the particular manufacturing craft 4, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature Tg+5 a ℃ of cladding glass; 7. particular manufacturing craft after the preheating 4 is arranged to have 52 ° of inclination angles, stand-by cast is taken out with glass metal 3, pour in the particular manufacturing craft 4; 8. after particular manufacturing craft 4 being put into fast the retort furnace that has been warming up to glass transformation temperature+10 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 3.5 ℃/hour speed, close the retort furnace power supply then, be cooled to room temperature automatically, obtain the glass preform 5 of single covering spiral optical fiber '; 9. with glass preform 5 ' on drawing wire machine, carry out wire drawing, obtain single covering spiral optical fiber.
Embodiment three: a kind of preparation method of special optical fiber, adopt the method for pouring caloric fusion, and concrete processing step is as follows: 1. use the material of tellurate as cladding glass, according to the prescription requirement of cladding glass, choose dusty raw materials and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add corundum and cover in silicon carbon rod electric furnace and found, temperature of fusion is 950 ℃, through fusing, stir and clarification back acquisition glass metal; 3. the temperature with glass metal drops to 800 ℃, is incubated 30 minutes; 4. glass metal is cast on the special-purpose excessively semicylinder casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain semicolumn glass stick 1; 5. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, 2., 3. repeating step uses glass metal 3 stand-by the cast that obtains then; 6. with semicolumn glass stick 1 and two plugs 2 combinations of obtaining, be placed in the particular manufacturing craft 4, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is the glass transformation temperature Tg of cladding glass; 7. particular manufacturing craft after the preheating 4 is arranged to have 60 ° inclination angle, stand-by cast is taken out with glass metal 3, pour in the particular manufacturing craft 4; 8. after particular manufacturing craft 4 being put into fast the retort furnace that has been warming up to glass transformation temperature+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 5 ℃/hour speed, close the retort furnace power supply then, be cooled to room temperature automatically, obtain the glass preform 5 of single covering twin-core fiber "; 9. " on drawing wire machine, carry out wire drawing, obtain single covering twin-core fiber with glass preform 5.This kind optical fiber can be used for optical fibre devices such as fiber switch, coupling mechanism, modulator, wavelength division multiplexer, wave filter.
Embodiment four: in the above-described embodiment, in 8. back repeating step operation 1.～8. of step, step 6. in the semicolumn glass stick 1 and glass preform 5 combinations that obtain, be placed in the particular manufacturing craft 4, and putting it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature Tg ± 5 ℃ of cladding glass; 7. particular manufacturing craft after the preheating 4 is arranged to have 45 °～60 ° inclination angles, stand-by cast is taken out with glass metal 3, pour in the particular manufacturing craft 4; 8. after particular manufacturing craft 4 being put into fast the retort furnace that has been warming up to glass transformation temperature Tg+5 ℃～glass transformation temperature Tg+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2～5 ℃/hour speed, close the retort furnace power supply then, automatically be cooled to room temperature, repeatedly repeat, obtain the glass preform (not shown) of many coverings special optical fiber.
In the foregoing description, plug 2 obtains with the following method: 1. according to the prescription requirement of glass of fiber core, choose raw material and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add a cover in silicon carbon rod electric furnace and found, temperature of fusion is 850～950 ℃, obtains glass metal after fusing, stirring and clarification; 3. reduce the temperature to 800 ℃, be incubated 30 minutes; 4. glass metal is cast on the casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature Tg fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2～5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the semicolumn glass stick; 5. take out this glass stick, on drawing wire machine, carry out wire drawing, obtain plug 2 through the polishing back.
In the foregoing description, glass transformation temperature Tg is for the glass of different components, and its numerical value is different fixed values.
Glass is a kind of supercooled liquid, that is to say, the hot entropy of its inside is than higher, and thermostability is poor, requires can not to heat up fast and lower the temperature gently so its thermograde changes.Characteristic according to glass, general tensile strength is σ S=0.035～0.085Pa, the about σ C=1.5～2Pa of ultimate compression strength, so can utilize its compressive property better to carry out the manufacturing of special shape optical fiber, this that is to say externally and is not easy explosion in the temperature-rise period, and fast cooling is easy to explosion, especially at the bigger low thermophase of cohesive force.Here adopt to be rapidly heated, the insulation fusion, methods such as slow cooling guarantee the stable in properties of glass.
In temperature-rise period, because temperature rise (Δ T
1), the pressure stress F of generation
L=K* Δ T
1, at Δ T
1During＜100 ℃/Min, F
L＜σ
S, wherein K is a stress coefficient.
The cast alloying process, to pour into a mould with glass metal 3 along θ=45 °～60 ° of tilted-putted mould sleeve pipes rapidly cast pour into, allow melt and slowly fusion after solid glass contacts, when having guaranteed cast with certain angle of inclination the elimination of bubble and interface closely.
At the fusion holding stage, the preheating temperature of bare glass is T
1, run into pyritous cast liquid (T
2) time, the temperature rise that brings because of conduction is Δ T
2So its soaking time is t
1=K
2* exp (T
2-Δ T
2), the stress that produce this moment can be ignored, because this moment, glass approached melt, viscosity is low.
The annealing holding stage at this moment, mainly is that the stress that the temperature non to fusion area brings is eliminated, and the holding temperature of choosing is (Tg ± 5 ℃) near this ANNEALING OF GLASS temperature.
The assurance of glass clarifying: the pyritous glass melt runs into lower temperature T after being poured in the particular manufacturing craft 4
2, promptly produce a quick temperature drop, thereby guaranteed the gamma transition process need.Glass combination is in the common warm with particular manufacturing craft 4, because be near softening temperature point Tg, so can keep original glass attribute on the basis that viscosity reduces.
The assurance of whole fusion clavate shape: glass assembly is below softening temperature point Tg in warm always, so its shape is kept intact fully, tiny glass plug 2 then positions with the mounting block on the particular manufacturing craft 4.Glass melt is in casting process, owing to being among the particular manufacturing craft 4 with fixed profile, so its shape also can be determined.The alloying process most critical part of glass assembly is that the high temperature that brings only can the melt-edge part, thereby combines fully and can not change shape.The particular manufacturing craft of corresponding profile is set as required, just can obtains the preform of respective shapes.
In the methods of the invention, follow the principle of the softening and cast of glass fully, Vitrea profile is determined to be implemented among the casting process, utilize the stress distribution of glass to carry out the fusion of glass.This is because when glass heats up, because the heat affected zone volumetric expansion can as long as this stress does not surpass the maximum compressive strength σ c of glass, just can not influence the shape of glass and produce stress crack producing stress under compression on every side; During cooling, adopt constant temperature method and annealing technology, crackle eliminates stress; During fusion, utilize the high temperature of cast liquid, melt colder firmware, realize that best welding and minimum stress generate, thereby the cast and the welding of glass are realized in a step fully, and the applying to plug 2 and covering needn't be tight fully in the used combination glass matrix, because having glass precursor solution to carry out nature when liquid fuses fills, thereby the operation when having simplified parent combination glass casting, only need the smooth outer surface of plug to get final product, realized the simpler production of special optical fiber prefabricated rods (comprising single-mode fiber here).
In sum, the inventive method is compared with MCVD gas phase partial corrosion method, has avoided its numerous and diverse operation (deposition, sintering, burn into contract rod or the like); Compare with the technology of the oval inner cladding optical fiber of preparation, need not to use the special technique that subtracts compressed rod; " stress embedment method " compared, and avoided desired ultrasonic drilling technology; " tiretube process " compared, avoid desired precise geometrical location and many glass sticks to be close to mutually and accurately guided the exhaust and the rod that contracts, " geometric Process " ratio, avoided the difficult processing problems of brittle glass again, and what process is complete seamless prefabricated rods, and drawing process is simple.In addition, existing various successful processing method, it is effective being used for preparing how much regular special optical fibers (as tie fiber, panda optic fibre, oval inner cladding optical fiber), but be used for the special more special optical fiber of preparation, especially at non-silica glass type optical fiber, then must on the basis of maturation method, introduce various special technical skill.From above-mentioned various embodiments as seen, the inventive method has very extensive applicability for the preparation special optical fiber." cast burning-on method " employed cast fusion mould, its major function and feature are, use in the alloying process of glass metal 3 formed daughters at the glass matrix that will form by semicolumn glass stick 1 and plug 2 and cast, what select is cast particular manufacturing craft 4, this mould not only possesses can realize the function of pouring into a mould fully, promptly guarantee the cast glass possibility, also possessing can fixing glass parent (half-cylindrical cladding glass and various doping plug).
The making of above-mentioned half-cylindrical cladding glass, can adopt a casting mold that is with small semicircle cylinder projection, glass plug 2 can be placed just in its position that depicts on semicolumn glass stick 1, according to symmetry distribution principle, separately make the special optical fiber prefabricated rods of required making is symmetric, plug 2 is fixed on the semicolumn glass stick 1 as parent.
Needed armamentarium is the casting mold that a cover cast conforms with dimensional requirement, add a plug and segment glass covering, form glass matrix, in the casting mold of special use the cortex glass precursor solution is poured in the mould according to certain angle, the insulation of annealing then just can obtain this single mode prefabricated rods.
Prepare twin-core fiber with the inventive method, also very simple, on corresponding two plug positions, two cylindrical protrusion are arranged in the mould that adopts, two grooves that can place plug are arranged on the glass block that feasible cast is come out, after in casting mold, combining female glass assembly, just can pour into a mould (in corresponding casting mold), can obtain complete prefabricated rods then.
Present patent application has disclosed " the cast hot melt is legal " of the special optical fiber of being invented and the embodiment that adopts the diversified special optical fiber of this method preparation, these embodiment only are that the some of the inventive method give an example, also be not limited to the material of tellurate as cladding glass, the inventive method also can be used to prepare other special optical fiber, and its basic inventive concept may be obvious that and obtains reasoning.
Claims (6)
1, a kind of preparation method of special optical fiber is characterized in that adopting the method for pouring caloric fusion, and concrete processing step is as follows: 1. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add a cover in silicon carbon rod electric furnace and found, temperature of fusion is 850～950 ℃, obtains glass metal after fusing, stirring and clarification; 3. the temperature with glass metal drops to 800 ℃, is incubated 30 minutes; 4. glass metal is cast on the special-purpose excessively semicylinder casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2～5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the semicolumn glass stick; 5. according to the prescription requirement of cladding glass, choose dusty raw materials and mix, then repeating step 2., 3., the glass metal that obtains is stand-by; 6. with the semicolumn glass stick and the combination of needed plug that obtain, be placed in the particular manufacturing craft, and put it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature ± 5 ℃ of cladding glass; 7. particular manufacturing craft after the preheating is arranged to have 45 °～60 ° inclination angle, stand-by glass metal is taken out, pour in the particular manufacturing craft; 8. after particular manufacturing craft being put into fast the retort furnace that has been warming up to glass transformation temperature+5 ℃～glass transformation temperature+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2～5 ℃/hour speed, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the glass preform of single covering special optical fiber; 9. glass preform is carried out wire drawing on drawing wire machine, obtain single covering special optical fiber.
2, the preparation method of a kind of special optical fiber as claimed in claim 1 is characterized in that the plug during described step is 6. is one, and this plug is arranged on the center of semicolumn glass stick, through step 6., 7., obtain single covering single-mode fiber 8. and 9..
3, the preparation method of a kind of special optical fiber as claimed in claim 1 is characterized in that the plug during described step is 6. is one, and this plug is arranged on the center of departing from of semicolumn glass stick, through step 6., 7., obtain single covering spiral optical fiber 8. and 9..
4, the preparation method of a kind of special optical fiber as claimed in claim 1 is characterized in that the plug during described step is 6. is two, through step 6., 7., obtain single covering twin-core fiber 8. and 9..
5, the preparation method of a kind of special optical fiber as claimed in claim 1 is characterized in that described plug obtains with the following method: 1. according to the prescription requirement of glass of fiber core, choose raw material and mix, until evenly; 2. the above-mentioned dusty raw materials that mixes is packed in the quartz crucible, add a cover in silicon carbon rod electric furnace and found, temperature of fusion is 850～950 ℃, obtains glass metal after fusing, stirring and clarification; 3. reduce the temperature to 800 ℃, be incubated 30 minutes; 4. glass metal is cast on the casting mold of preheating, putting near the retort furnace that has been warming up to the glass transformation temperature fast anneals, cycle of annealing is: insulation earlier 2 hours, be cooled to 100 ℃ with 2～5 ℃/hour speed then, close the retort furnace power supply then, automatically be cooled to room temperature, obtain the fibre core prefabricated rods; 5. take out this fibre core prefabricated rods, on drawing wire machine, carry out wire drawing, obtain plug through the polishing back.
6, the preparation method of a kind of special optical fiber as claimed in claim 1, it is characterized in that 1.～8. at the 8. back repeating step of step, step 6. in the semicolumn glass stick and the glass preform combination that obtain, be placed in the particular manufacturing craft, and putting it in the holding furnace preheating 20 minutes, the temperature in the holding furnace is glass transformation temperature ± 5 ℃ of cladding glass; 7. particular manufacturing craft after the preheating is arranged to have 45 °～60 ° inclination angles, stand-by glass metal is taken out, pour in the particular manufacturing craft; 8. after particular manufacturing craft being put into fast the retort furnace that has been warming up to glass transformation temperature+5 ℃～glass transformation temperature+15 ℃ and being incubated 20 minutes, be cooled to 100 ℃ with 2～5 ℃/hour speed, close the retort furnace power supply then, automatically be cooled to room temperature, repeatedly repeat, obtain the glass preform of many coverings special optical fiber.
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| CNB2005100493368A CN100345781C (en) | 2005-03-11 | 2005-03-11 | Method for preparating special optical fiber |
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| CNB2005100493368A CN100345781C (en) | 2005-03-11 | 2005-03-11 | Method for preparating special optical fiber |
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| CN100345781C true CN100345781C (en) | 2007-10-31 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101117266B (en) * | 2007-07-18 | 2010-12-08 | 宁波大学 | Method for preparing tellurium-based glass fibre-optical prefabricated rod |
| CN103241937B (en) * | 2013-05-10 | 2015-07-01 | 南京邮电大学 | Die for pouring special optical fiber perform and adjuster thereof |
| CN107631917B (en) * | 2016-07-18 | 2021-12-21 | 中国电力科学研究院 | Device and method for curing and molding superconductor test sample |
| CN108081521B (en) * | 2016-11-22 | 2021-08-06 | 中国电力科学研究院 | Forming device for composite resin impregnated superconductor |
| CN111792835B (en) * | 2020-06-18 | 2022-08-05 | 广州宏晟光电科技股份有限公司 | Glass capillary tube and preparation method thereof |
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| CN87104844A (en) * | 1986-07-14 | 1988-01-27 | 菲利浦光灯制造公司 | The method that has the optical fiber of fibre core and cladding of glass with the rod-in-tube technique manufacturing |
| US5160520A (en) * | 1990-06-23 | 1992-11-03 | Kabelmetal Electro Gmbh | Process for the production of a blank mold for glass fiber optical waveguides |
| EP0729919A2 (en) * | 1995-03-01 | 1996-09-04 | Sumitomo Electric Industries, Ltd. | Optical fiber and method of manufacturing the same |
| CN1396131A (en) * | 2002-07-09 | 2003-02-12 | 长飞光纤光缆有限公司 | Process for preparing quartz optical fibre core |
| JP2003212581A (en) * | 2002-01-21 | 2003-07-30 | Sumitomo Electric Ind Ltd | Method for producing polarization maintaining fiber |
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- 2005-03-11 CN CNB2005100493368A patent/CN100345781C/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87104844A (en) * | 1986-07-14 | 1988-01-27 | 菲利浦光灯制造公司 | The method that has the optical fiber of fibre core and cladding of glass with the rod-in-tube technique manufacturing |
| US5160520A (en) * | 1990-06-23 | 1992-11-03 | Kabelmetal Electro Gmbh | Process for the production of a blank mold for glass fiber optical waveguides |
| EP0729919A2 (en) * | 1995-03-01 | 1996-09-04 | Sumitomo Electric Industries, Ltd. | Optical fiber and method of manufacturing the same |
| JP2003212581A (en) * | 2002-01-21 | 2003-07-30 | Sumitomo Electric Ind Ltd | Method for producing polarization maintaining fiber |
| CN1396131A (en) * | 2002-07-09 | 2003-02-12 | 长飞光纤光缆有限公司 | Process for preparing quartz optical fibre core |
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Assignee: Chengdu Jinghua Photoelectric Technology Co., Ltd. Assignor: Ningbo University Contract record no.: 2011330000548 Denomination of invention: Method for preparating special optical fiber Granted publication date: 20071031 License type: Exclusive License Open date: 20250310 Record date: 20110518 |
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