CN1060361A - The manufacture method of silica glass optical waveguded preform - Google Patents

Abstract

Have at least two independent inlets and an outlet of being led to and making in the extrusion equipment of at least two passages that its correspondence leads to, the junction surface section of passage constitutes by central portion and periphery are concentric, supply with core material and covering material through the corresponding court that enters the mouth respectively with the passage that central portion, periphery lead to, both are joined in the junction surface.Squeezing out central portion from outlet has and the fuse appropriate section, around this central portion shaping body with the covering appropriate section is arranged, and disposes water, bonding agent and other impurity from the latter, again with solidization of formed body of gained.

Description

The manufacture method of silica glass optical waveguded preform

The present invention relates to be used for forming used optical fiber in optical communication or the light word field, pass the manufacture method that resembles fiber or pass the prefabricated component of fiber optics and so on optical waveguide.

In optical communication or optical field, in order to form glass preform for optical fiber, to pass and to resemble fiber preform or to pass the fiber optics prefabricated component, adopted and crossed the VAD(vapor-phase axial deposition already) the CVD(chemical vapor deposition of method and so on) method, MCVD(modified chemical vapor deposition) method, the outer gas deposition of OVD() method, or the PCVD(plasma chemical vapor deposition) method, casting method or the two method that combines of CVD method and sol-gel process.

In the CVD method, adopt SiCl ₄Or GeCl ₄And so on halogenide be starting material.This kind starting material form SiO through oxidation or flame hydrolysis ₂Or GeO ₂Oxide powder, the powder of Xing Chenging is gone up and is grown by depositing to a predetermined depositional plane (for example surface of the inner peripheral surface of the terminal surface of target, quartz ampoule or plug) like this.The solid then prefabricated component that changes into of powder on the deposition.

Recently, also adopted the device of making prefabricated component according to complete synthetic VAD method, to obtain optical fiber with better quality.

In the manufacture process of single mode optical fibre prefabricated component, for example be porous vitreum that fuse and covering are used by suitable external diameter than synthetic simultaneously by the VAD method, solidization then.Afterwards, for obtain required fuse/covering place directly than, the porous vitreum that covering is used deposits on the transparent vitreous body that is made by the OVD method, goes solidization again.

In the casting method, for example Japan's special permission is openly applied in 64-56331 number disclosed, be that quartz glass powder is disperseed to form in the glass water powder slurry, then this powder slurry being injected makes the contained water of powder slurry remove by the hole on the mould in the mould, the result has just formed the porous vitreum of being made up of this glass powder, makes this porous vitreum drying, purification and solidization then.

The sort of with in CVD method and the method that sol-gel process combines, for example Japan special permission is openly applied in 1-294584 number disclosedly, is that the two is combined into one for linden shape porous vitreum (glass of fiber core+part cladding glass) that will be mainly made by the CVD method with pipe linden method and the tubulose porous vitreum (remainder of cladding glass) that is made by sol-gal process.Then these a few many solidization of vitreums while.

Still there are following technical matterss in the method that above-mentioned DVD method, casting method and CVD method combine with sol-gel process.

In the CVD method, although it is very high to obtain the complete degree of technology of specification product, the deposition efficiency of oxide powder is low to reach 30% to 50%, and device size increases owing to needing to handle waste gas simultaneously, so problems such as productive rate, manufacturing expense and equipment economy have just been arranged.

The casting method can be produced high-quality porous vitreum expeditiously with simple device.But list can not produce waveguiding structure in this way.

So the casting method must be improved or is used in combination with another kind of method aspect above-mentioned, has proposed this class methods yet there is no the prior art relevant with the casting method.

In the method that combines CVD method and sol-gel process, have like this some problems, for example the cost of alkoxide is very high in the raw material, and easily cracking in drying of jel product, is difficult to increase the size of prefabricated component.

As the method for making of waveguide with prefabricated component, except that the above several, still adopting has for example Japan's special permission openly to apply among 60-2105539 and the 61-266325 and " Glastech:Ber " 60(1987) in disclosed MSP(mechanical molding prefabricated component) the method for making of gas preform.

In a kind of method in back, adopt coaxial spiral shell to walk back and forth quartzy fine powder material and covering filling that feed appliance uses fuse also is compressed in the quartz glass tube.And then with this solidization of porous preform of taking out in the quartz glass tube.

In this kind MSP method, fuse and covering two parts are to be formed on simultaneously in the quartz glass, and formed vitreum often has unevenness, make generating bubble in prefabricated component, and formed bubble just will cause for example scattering loss in the optical fiber of final products in solid process.

In addition, in this MSP method of quartz glass tube as mould, the size of prefabricated component is determined in inconvenience.

The present invention has considered above situation, and to provide a kind of novel method of making silica glass optical waveguded preform to be its purpose.

Another object of the present invention is to provide a kind of can be rationally and make the method for high-quality silica glass optical waveguded preform economically.

The method of manufacturing silica glass optical waveguded preform provided by the invention may further comprise the steps:

Prepare an extrusion apparatus that has two inlet portions at least, the passage that this equipment still has an export department of linking up with above-mentioned inlet portion and at least two that this kind inlet portion and export department are led to, the section at the junction surface of these passages has the central part and the peripheral part of concentric arrangement;

One of passage of giving the central part that is leading to above-mentioned junction surface from a corresponding inlet portion is supplied with core material, supplies the covering material from a corresponding inlet portion to the passage that another and aforementioned peripheral part lead to simultaneously, so just makes these two kinds of materials join mutually at this place, junction surface;

Squeeze out the suitable core material of a middle body and around the shaping body of the suitable clad section of this middle body person from above-mentioned export department;

From then on remove impurity in the shaping body; And

With this solidization of finally making of shaping body.

According to the present invention, can will be combined into integral body, and can in these two parts, not entrain into the material that can form bubble corresponding to the part of core material with corresponding to the part of covering.Therefore, can have very high-quality optical waveguded preform with high yield manufacturing with low-cost.

Other purposes of the present invention and advantage will be described in down, and be able to obtain understanding partly from this describes or by implementing the present invention.Above-mentioned purpose of the present invention and advantage can be by the device specifically noted in the appended claim book and combination thereof accomplished.

Be included in this instructions and constitute its a part of accompanying drawing and be used for illustrating that the present invention is current thinks the genus illustrated embodiments, simultaneously as the detailed description of most preferred embodiment being explained principle of the present invention in conjunction with general description in front and back.

Fig. 1 is a side view, shows the bright equipment that is used for implementing first embodiment of the invention;

Fig. 2 is a sectional view, shows the crosshead of equipment shown in bright Fig. 1;

Fig. 3 has schematically shown among first embodiment connection status between the used glass bar and an attached rod;

Fig. 4 is a planimetric map, shows the bright equipment that is used for implementing second embodiment of the invention;

Fig. 5 is a sectional view, shows the crosshead of equipment shown in bright Fig. 4;

Fig. 6 and 7 is a sectional view, shows the crosshead in the equipment of bright the 3rd embodiment that is used for implementing the present invention, and

Fig. 8 is the sectional view that is used for implementing crosshead in the present invention's the equipment of the 4th embodiment.

Each most preferred embodiment is described in detail in detail below

Among the present invention, in an extrusion equipment, be formed with at least two inlet portions.A supply core material from these inlet portions, and from another inlet portion supply covering material.These two kinds of materials are joined at a junction surface with concentric profile pattern, squeeze out from an export department simultaneously, form face portion in thus corresponding to that part of then corresponding to the shaping body of covering around this middle body of core material.Make this shaping soma dry, it is implemented remove oil stain step and purifying step then.Removing oil stain step by this removes and contains bonding agent in the shaping piece.Remove OH base and other metallic impurity contained in the shaping piece by purifying step as impurity.Solidization of shaping body that will make so then is in order to make optical waveguded preform.

A kind of plastic material that contains fused silica powder can be as the clad material here.The glass bar that mainly contains quartz glass or be made up of a kind of plastic material that contains fused silica powder then can be used as corresponding core material.The above-mentioned plastic material that contains fused silica powder refers to a kind of material of producing according to following manner, promptly water, add pure fused silica powder to a kind of shaping assistant (bonding agent) more in case of necessity or be added with in the pure fused silica powder of minute quantity adulterant, their are evenly mediated to make becomes a kind of final compliant material.

This kind fused silica powder that is added with the minute quantity adulterant comprises: the powders mixture that pure fused silica powder and this adulterant powder are formed; With a kind of solution state, for example acetate, nitrate or the pure salt form with this adulterant adds in the pure quartz glass powder with this adulterant; And a kind of fused silica powder that contains adulterant that is combined into by CVD.

When the glass bar of mainly being made up of quartz glass was used as core material, the passage from the core material inlet portion to the junction surface in the above-mentioned extrusion equipment must be straight.

When being core material with the quartz glass bar, such quartz glass bar is preferably made by the CVD method of VAD method and so on.One of reason is can make in high quality with technical almost completely mature C VD method as the glass bar of prefabricated component core material.Another reason is that shared volume ratio can be very little in prefabricated component for glass bar.In other words,, say on the whole,, also just reduced the reduction of productive rate owing to avoided the increasing device size even the deposition efficiency of the oxide powder that is obtained by the CVD method is low.

In addition, when a kind of drip molding drying that is used as glass bar surface top covering material, purification and solidization, owing to there is no bubble in the glass bar as core material, and be can not be diffused in the glass bar and outwards loss by the bubble that glass dust comes formed body to generate, thereby bubble is to tie up very much existence.

When particularly some was used as core material when the cladding glass surface portion, the interface of core material and covering was can not keep bubble.Even,, be can not produce above-mentioned scattering loss also because this bubble place part is formed on the outside at core material and covering interface when clad material leaves bubble in solidization process.Therefore, there is the glass bar of part cladding glass can be used as core material better on the surface.

When glass bar when the core material, need only join in the corresponding separately passage with this glass bar with as the plastic material of covering material, on the surface of this glass bar, to form the organizator of glass powder.So, can form required formed body in high quality by the device and the simple operation of economy.In addition, this formed body as clad material only needs drying, purification and solidization in aftertreatment.

Simultaneously also since the core material in the prefabricated component partly be one on physical property stable glass bar (hard material), the glass powder formed body (plastic material) that is formed on this glass bar just can obtain stable support.Therefore, even be that the glass powder formed body with big external diameter also is easy to form.

So when producing optical waveguded preform as stated above, the quality of prefabricated component is improved, its productive rate can improve, thereby has reduced cost of products, obtains a kind of very economic production method therefrom.

When as core material being, the plastic material of this kind core material and covering need only be joined in the extrusion equipment a kind of shaping body of extrusion molding-be molded into to the plastic material that contains quartz powder.Because this shaping body can be made with simple operation by the device of economy, just can realize high-quality and high yield.

Describe the present invention below in greater detail.

Fig. 1 is the side view that is used for implementing the equipment of first embodiment of the invention, and Fig. 2 is the sectional view that shows a crosshead in bright this equipment.

Order is being provided with being coupled and is having motor 12, the main kneading compartment 14 with funnel 13, vacuum chamber 15 and a secondary kneading chamber 16 that passes a device on support 11.One spiral (not showing bright) is housed, by motor 12 and a transmission shaft 17 driven rotary in the main kneading compartment 14; Be equipped with and a spiral (not showing bright) in the secondary kneading compartment 16, by motor 12 and a transmission shaft 18 driven rotary.Crosshead 20 is installed on the support 19.

As shown in Figure 2, have on the crosshead 20 two independently inlet portion 21 and 22, public export departments 23, extend to two passages 24 and 25 of export department 23 from inlet portion 21 and 21, and one be formed on inlet portion 21 and 22 and export department 23 between junction surface 26, and above-mentioned two passages 24 and 25 are promptly mutually in this junction.At the junction surface 26, passage 24 can synthesize with 25 mutual benevolence and has concentric profile pattern.

Deposit at above-mentioned cloth, passage 24 is got straight form with respect to junction surface 26.

In crosshead 20 with said apparatus mode, there is not a glass bar to supply with machine (not showing bright) in the side of inlet portion 21,22 of another inlet portions lead to secondary kneading compartment 16.

Insert quartz glass bar 31 as core material from inlet portion 21, the latter is that the CVD method by VAD method and so on forms.

Glass bar 31 can be to be formed by core material glass 32, or can be on its surface portion some cladding glass 33, as shown in Figure 3.

As shown in Figure 3, seam has the attachment rod of a tool suitable length on the one or both ends of glass bar 31, is used as the supporting member in the extrusion die or draws materials and parts.

Be used as the material of above-mentioned attachment bar 34, except the quartz glass identical, for example still have a pottery and a mouthful position to be lower than quartzy glass with glass bar 31.

Plastic material 35 as clad material mainly is made up of fused silica powder, and the granularity of this fused silica powder is preferably 100um or littler.

Except above-mentioned main material,, can add the adulterant of fluorine-based or boryl as required as refractive index control material to the main material of this plastic material 35.

Above-mentioned plastic material 35 is pure water, in case of necessity again with a kind of shaping assistant (bonding agent), join quartz glass powder or add in the quartz glass powder that small amounts of dopants is arranged, the material of such gained of evenly kneading then makes it to possess plasticity.

Said shaping assistant is organic substance and dead matter, and the former for example is polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl butyral, polyglycol, methylcellulose, carboxymethyl cellulose, ethyl cellulose, hydroxypropyl cellulose and glycerine; The latter for example is the colloidal state quartz.

The addition of the auxiliary Ji in full bloom of this class in the plastic material 35 is about 1-20(weight % with respect to glass powder).

Plastic material 35 adds from inlet portion 22.The inlet portion of recognizing plastic material 35 can be opened on a plurality of positions, for example can form another inlet portion at the opposite side of this inlet portion 22.Utilize this arrangement, this kind can more easily evenly supply on the surface of glass bar 31 as the plastic material of clad material.

The operation of the above embodiment of the present invention is described below.Be connected to the attachment rod 34 on glass bar 31 1 ends, supply with machine (not showing bright) by the glass bar that is arranged on crosshead 20 inlet portions 21 sides and kept, the end of this glass bar 31 is inserted in the inlet portion 21 of crosshead 20.When plastic material 35 after funnel 13 is updated to main kneading compartment 14, above-mentioned glass bar is supplied with machine and motor 12 just starts, and makes associated components enter duty.

As a result, glass bar 31 is just supplied with machine by glass bar and is supplied in the passage 24 by the inlet portion 21 of crosshead 20, and the plastic material 35 in the main kneading compartment 14 is promptly by vacuum chamber 15 and secondary kneading compartment 16, with predetermined extruding rate in inlet portion 22 admission passages 25.

Above-mentioned glass bar 31 is joined at 26 places, junction surface of crosshead 20 mutually with plastic material 35.As previously mentioned, there is a concentric profile pattern at this junction surface 26, and promptly its middle body is corresponding with passage 24, and its neighboring part is then corresponding to passage 25.So the surface of glass bar 31 just is that plastic material 35 covers.

Glass bar 31 and plastic material 35 are integrally to squeeze out from the export department 23 of crosshead 20, form a kind of like this body 37 in full bloom therefrom, wherein promptly are formed on the surface of glass bar 31 by the porous vitreum 36 that aforementioned plastic material is formed.

Then with baking oven with these body 37 dryings in full bloom, remove the moisture content in the porous vitreum 36, and the stain (removing bonding agent) of deoiling is handled in a debinding furnace.

Then do purified treatment and the processing of solidization in succession according to conventional methods, make prefabricated component at last.

It is also noted that glass bar 31 preferably closes on inlet portion 21 and adds at the part place that joins being supported on, the result can restrain the degree of eccentricity of core material in the prefabricated component and further improve the quality.

Second embodiment of the present invention is described in down.

Fig. 4 is the section that is used for implementing the equipment of second embodiment of the invention, and Fig. 5 is the sectional view that shows crosshead in bright this equipment.

In the extrusion apparatus shown in Fig. 4 and 4, two extruders 41 and 51 are arranged by a crosshead 61 vertical cartels.

Referring to Fig. 4, wherein extruder 41 is equipped with in motor 42, the main kneading compartment 44 that funnel 43 is arranged, vacuum chamber 45 and a secondary kneading compartment 46, the main kneading compartment 44 of the belt driver of continuous mutually coupling connection and is equiped with spiral (not showing bright), by a motor 42 and a rotation axis (not showing bright), by motor 42 and a rotation axis (not showing bright) driven rotary.

Among Fig. 4 another extruder 51 also be equipped with mutually the belt driver of continuous coupling connection motor 52, the main kneading compartment 54 of funnel 53 is arranged, a vacuum chamber 55 and a secondary kneading compartment 56.Be equipped with in the main chamber 54 by motor 52 and the spiral (not showing bright) that transmission shaft (not showing bright) drives, be provided with another spiral that drives for motor 52 and transmission shaft (not showing bright) in the concubine 56.

Crosshead 61 shown in Fig. 5 has two independently inlet portion 62 and 63, public export departments 64, two passages 65 and 66 that extend to export department 64 from inlet portion 62 and 63, and one be formed on inlet portion 62 and 63 and export department 64 between junction surface 67, at this place, junction surface, two passages 65 and 66 are joined mutually.67 places at the junction surface, passage 65 and 66 mutual concentric junctions.

In the said apparatus mode, passage 65 leads to the middle body at junction surface 67, and another passage 66 leads to its peripheral part.

In the crosshead 61 with said apparatus form, the secondary kneading compartment 46 of extruder 41 and an inlet portion 62 lead to, and the secondary kneading compartment 56 of extruder 51 then leads to another inlet portion 63.

As the plastic material 71 of core material 41 is to supply with from inlet portion 62, then is to be supplied with by inlet portion 63 as the plastic material 73 of clad material.These two kinds of plastic materials all mainly are made up of the quartz glass powder.

Remove the SiO that is used as main material ₂Outward, with a kind of compound for example GeO-2, P ₂O ₅, TiO ₂Or Al ₂O ₃Join in the plastic material 71 as adjuvant, in order to control (raising) refractive index as required.On the other hand, with B ₂O ₃Or the compound of F and so on is as main material SiO ₂Outside adjuvant join in the plastic material 73, be used for control (reduction) refractive index.

Above-claimed cpd mixes with the powder form or adds as the solution of acetate, nitrate or alkoxide.Other method can be by the synthetic quartz glass powder that contains this compound of CVD method.

Above-mentioned plastic material 71 and 73 can be fully according to the same procedure preparation of plastic material among first embodiment.

Should know,, be used for supplying with inlet portion as the plastic material 73 of clad material as the situation among first embodiment, be can be located at numerous locational.

The operation of the above embodiment of the present invention is described below.

Plastic material 71 is in funnel 43 is supplied in main kneading compartment 44, and plastic material 73 then adds from funnel 53 becomes owner of in the kneading compartment 54.CD- ROM drive motor 42 and 52 is pressed set rate and is supplied with plastic material 71 and 73.

When turning round this extrusion apparatus according to aforesaid way, as shown in Figure 5, plastic material 71 in the main kneading compartment 44 supplies in the passage 65 with secondary kneading compartment 46 by vacuum chamber 45 from the inlet portion 62 of crosshead 61, and the plastic material 73 in the main kneading compartment 54 then supplies in the passage 66 through vacuum chamber 55 and secondary kneading compartment 56 from the inlet portion 63 of crosshead 61.

Plastic material 71 and 73 is mutually joined at the junction surfaces 67 of crosshead 61, and forming one has fritted glass to stop 72 as fuse at the center, has fritted glass to stop 74 formed bodies 75 as covering in the neighboring.This formed body 75 promptly squeezes out from export department (mould portion) 64.

Thereafter, formed body 75 is anhydrated by the dryer drying, and in debinding furnace degrease (bonding agent).

Follow-up with solidization processing according to conventional method thereupon in purified treatment, obtain a prefabricated component thus.

The third embodiment of the present invention is described in down.

In each of aforesaid first and second embodiment, each corresponding inlet of core material and covering material is got mutual arranged perpendicular form.In this 3rd embodiment, the axes intersect of these two inlet portions becomes the angle less than 90 °.

Be arranged into oral area according to aforesaid way, clad material just can flow more equably, is reduced to strain or the even property of density unevenness in the body.

Fig. 6 and 7 is equivalent to Fig. 2 and 5 respectively, is used for implementing the sectional view of crosshead in the equipment of the 3rd embodiment.In Fig. 6,22 places are formed with inlet portion 82 in inlet portion shown in Figure 2.In Fig. 7,63 places are formed with inlet portion 83 in inlet portion shown in Figure 5. Inlet portion 21 and 82 shown in Fig. 6 is the angle [alpha] that defines of axis separately, and the inlet portion shown in Fig. 7 62 and 83 angle beta that respectively meets axis to define, all is set at less than 90 °.

In this embodiment, can make optical waveguded preform according to the method among first and second embodiment with equipment shown in Fig. 6 and 7.

The fourth embodiment of the present invention is described below.In this embodiment, the diameter of export department can change, so that the external diameter of formed body is carried out meticulous adjusting.Like this, even when the external diameter of fuse bar has slightly the off-design value in the manufacture process of prefabricated component, also need to change mould and just can adjust external diameter in the exit.

Fig. 8 is the sectional view that is used for implementing the four-way union in the equipment of this embodiment.Because the basic structure and the crosshead shown in Fig. 2 of this crosshead are similar, just omitted with the description that identical portions among Fig. 2 is individual.

Epidemic disease has a kind of distensible annular die 91 in the inner peripheral surface of the crosshead middle outlet portion 23 here, is used for regulating the diameter of this export department 23.

Mould 91 is made of the elastic-like material of rubber or synthetic resin.

Mould 91 is assembled in export department 23 and makes inner circumferential surface concordant with the inner peripheral surface of export department 23.

On the outer peripheral face of mould 91, be provided with a head tank 92, mould 91 is radially shunk and expansion.

Head tank 92 is made up of a kind of ring-shaped article, and a hollow parts 93 is arranged within its outer peripheral portion.The section of this hollow parts 93 takes the shape of the letter U.

These head tank 92 sealings also are embedded in export department's 23 1 thick wall parts, and are able to contact with the outer peripheral face of mould 91.Be provided with through hole 94 in the outer peripheral face of outlet 23, to be communicated with the hollow parts 93 of head tank 92.

For example have fluid slot, a pump and valve piping system 95 of (all not showing bright) with a kind of, the above-mentioned through hole 94 and the hollow parts 93 of head tank 92 are led to.Referring to Fig. 8, this kind piping system has to inject discharges two kinds of functions of fluid.

The fluid 96 that is supplied in the hollow parts 93 of head tank 92 from piping system 95 can be liquid or gas, can select among the two suitable a kind of.But fluid 96 is water preferably, because the ratio of compression of water is very low, and economy is carried with being easy to.

Can adopt a kind of so hollow endless belt with regard to head tank 92, the upper surface of its hollow space 93 seals.

In said structure, owing to be that the hollow space of this endless belt is used as hollow parts 93, the connecting hole that is used for leading to piping system 95 just is opened on the outer peripheral portion of this endless belt (head tank 92).

Do not adopt the sort of annular element or above-mentioned hollow type endless belt can form head tank 92 with hollow parts 93 yet.Here it is the part of the export department 32 with the assembly space that is used for assembling and support a kind of ring or strap-like member, directly is used as head tank 92.

In said structure, this assembly space of export department 23 all is hermetic closed except that through hole 94.

In addition, in the above-described embodiments, also can make optical waveguded preform according to the same procedure of first embodiment.

Example 1

This example is corresponding with the present invention's first embodiment.

What adopt as quartz glass bar 31 is a kind of like this glass bar, and its core material glass 32 is by SiO ₂-GeO ₂Form, and the part of cladding glass 33 is by pure SiO ₂Form.

Above-mentioned glass bar 31 is to be formed by the VAD method.The external diameter ratio of 32 pairs of cladding glasses 33 of core material glass is 1: 3, and the specific refractivity difference △ that core material glass 32 and cladding glass are 33 is 0.3%.The diameter of glass bar is 8mm, and length is 600mm.

8mm diameter and the long attachment rod 34 of 300mm by quartz glass is formed by the glass welding, become the supporting member of above-mentioned glass bar 31 1 ends.

Plastic material 35 makes by following mode, and methylcellulose is joined the quartz (SiO that particle mean size is 8um as bonding agent ₂) in the powder, mix this two kinds of materials, with the knead potpourri of gained of pure water.Quartz powder materials: methyl fiber number: the mixing ratio of pure water is 100: 3: 22.

Relevant devices is carried out operation according to above-mentioned identical method.

Glass bar 31 is supplied with machine by glass bar and is supplied in the passage 24 from the inlet portion 21 of crosshead 20, and the plastic material 35 in the main kneading chamber 14 is from vacuum chamber 15 and secondary kneading compartment 16, by the inlet portion 22 of crosshead 20, supplies in the passage 25 by the speed of 30kg/h.

26 places squeeze out from the export department 23 of crosshead 20 after the meeting at the junction surface for above-mentioned glass bar 31 and plastic material 35.The result has made a formed body 37, and wherein 36 of the porous vitreums of being made up of plastic material 35 are formed on the surface of glass bar 31.

The time of finishing above-mentioned squeeze job needs 15 minutes.

After plastic material 35 had been formed on glass bar 31 already and had been attached on the rod 34, only need remove and be deposited on the porous body 36 that attachment rod 34 lip-deep glass powder material form, then in a dryer, under 110 ℃, be dried at the porous vitreum on the glass bar 31 36.The removing oil stain that carried out under 500 ℃ then 4 hours is handled.

The porous body 36 of having removed the glass powder formation of oil stain has the external diameter of about 50mm and about 60% relative density.

And then this porous vitreum 36 is made suburb processing (He/Cl according to conventional method ₂Under the atmosphere, 1200 ℃) and solidization processing (under the He atmosphere, 1600 ℃), make a glass preform for optical fiber thus.

Continue after this prefabricated component is carried out wire-drawing operation, form the single mode optical fibre of external diameter 125um, use the ultraviolet-curing resin coating immediately after the wire drawing, make this fibre-optic external diameter 400um.

The optical fiber of this coating that makes, its transport property is with mainly the complete synthetic prepared optical fiber of VAD method by routine is suitable.

Example 2

This example is corresponding with the present invention's second embodiment.

Plastic material 71 makes by following mode: the aqueous solution of 10%PVA is added to a kind of quartz powder materials (GeO that contains 3.5 weight % ₂As the adulterant that improves refractive index) in, the latter is synthetic by flame hydrolysis, and particle mean size is 0.7um, and the powder material is 100: 36 to the ratio of solution, and these two kinds of materials are evenly kneaded.

Plastic material 71 is by will be as the methylcellulose of bonding agent and pure water, and add in the quartz powder materials that particle mean size is 8um making powder herein: methylcellulose to: pure water equals 100: 3: 32, and this different materials is through evenly mediating.

In used extrusion apparatus, the end diameter of passage 65 is 4mm, and the end diameter at junction surface 67 is 50um.

Plastic material 71 is added in the main kneading compartment 44 by funnel 43, and plastic material 73 then is supplied in main kneading compartment 54 through funnel 53.CD- ROM drive motor 42 and 52 makes the extruding rate of plastic material 71 and 73 remain 0.2kg/h and 40kg/h respectively.Plastic material 71 in the main kneading compartment 44 is to enter in the passage 65 with secondary kneading compartment 46 through vacuum chamber 45 from the inlet portion 62 of crosshead 61, and the plastic material 73 in the secondary kneading compartment 54 be from inlet portion 63 in vacuum chamber 55 and secondary kneading compartment 56 admission passages 66.

Above-mentioned two kinds of plastic materials 71 and 73 are joined at 67 places, junction surface at crosshead 61 places mutually, and having formed the center is fuse with porous vitreum 72, and the neighboring is the formed body 75 of covering with porous vitreum 74.This formed body 75 is by squeezing out in the export department of crosshead 61 (mould portion) 64.

Finishing the required time of above-mentioned squeeze job is 15 minutes.

The formed body 75 that mold pressing goes out is dry under 110 ℃ in dryer, and the oil stain that removes that carried out under 500 ℃ then 4 hours is handled.

Formed body 75 after above-mentioned processing has the external diameter of about 48mm and about 57% relative density.

Above-mentioned formed body 75 is in drying and after removing the oil stain processing, process purification and solidization are to form glass preform for optical fiber again.

Dehydration is at He/Cl with purified treatment ₂Under 1200 ℃, carry out in the atmosphere, generally according to conventional method.

Then above-mentioned prefabricated component being drawn into the footpath with known method is the single-mode fiber of 125um, is right after the coating of being made up of ultraviolet-curing resin that promptly forms external diameter 400um after the wire drawing on this fibre-optic outer peripheral face.

The transport property of the optical fiber institute tool of the coating of this example 2 is suitable with the optical fiber that is mainly made by the synthetic VAD method of the meeting of routine.

Example 3

This example is corresponding with the present invention's the 3rd embodiment.

In used equipment, the angle [alpha] that is defined by the axis of inlet portion shown in Figure 6 21 and 28 is defined as 60 °.

Use the said equipment, prepare a formed body according to the same procedure in the example 1.The even property of the strain of this kind formed body and density unevenness is less than the formed body in the example 1.

This formed body that makes according to the same quadrat method in the example 1 form in profile and the example 1 identical glass preform for optical fiber in addition, also prepare coated optical fiber according to the same quadrat method in the example 1.

The transport property of this kind coated optical fiber institute tool is suitable with the main optical fiber that is made by the complete synthetic VAD method of routine.

On the other hand, prepared a kind of equipment, wherein the angle beta that is defined by the axis of inlet shown in Figure 7 62 and 83 is defined as 60 °.

The same procedure that such equipment is used to examine as a rule in 2 is made a formed body.The even property of the strain of this kind formed body and density unevenness is all less than the formed body in the example 2.

Above-mentioned formed body is handled according to the same procedure described in the example 2, forms the identical glass preform for optical fiber in a profile and the example 2.In addition, also according to the optical fiber that has made coating in the example 2 accordingly with quadrat method.

This coating optics silk ribbon is tieed up the transport property of institute's tool, and is suitable with the main optical fiber that is made by the complete synthetic VAD method of routine.

Example 4

This example is corresponding with the fourth embodiment of the present invention.

In Fig. 8, the end diameter at described junction surface is 55mm, and the internal diameter of mould 91 is recalled and is 55mm.Here be with water (fluid 96) as pressure medium by making its expansion in the piping system 95 injection pressure jars 92.As a result, mould 91 is shunk diametrically reduce, the diameter of mould becomes 50mm.Adopt this kind device mode, just can be according to the same quadrat method in the example 1, similar glass bar and plastic material carry out squeeze job in application and the example 1.

Here, pressing the core material rod outside diameter of 8mm design, is 1: 2.9 because the unevenness of the corrosion of HF has become the external diameter ratio of 7.8mm(covering and fuse).For be engaged in this kind core material rod with example 1 in similar squeeze job, need be the water that is used as pressure medium (fluid 96) emptying from head tank 92, so that the internal diameter of mould 91 is adjusted to 52mm.When the internal diameter that the internal diameter of mould 91 is connect son 91 is adjusted to 52mm.Above being pressed, the internal diameter of mould 91 after the described setting, just carries out squeeze job.The result makes an external diameter 52mm, the formed body of long 600mm.

Obtained a prefabricated component after this formed body being handled with quadrat method according to example 1 is described, handled drawing out optical fiber again according to the same procedure in the example 1.In single-mode fiber of finally making and the example 1 with required profile quite.

Notice in above each example it is that single mode optical fibre is come usefulness as an example, and and consult optical fiber is restricted to this type.In addition, the present invention is not limited to learn fiber preform, and goes for other optical waveguide, for example passes to resemble fiber and pass fiber optics.

The people who is familiar with this technology can draw other advantage and improved pattern immediately.So the present invention is from its each side widely, be to be not limited to detail described here and as case illustrated etc.Therefore, under the prerequisite of the spirit or scope of the general creative notion that does not break away from appended claim book and content defined of equal value with it, can make various remodeling.

Claims (10)

1, make a kind of method of silica glass optical waveguded preform, it may further comprise the steps:

Prepare an extrusion equipment, it has: at least two inlet portions (21,22 independently; 62,63), one and above-mentioned inlet portion (21,22; 62,63) export department of Gou Tonging (23,64), with this kind inlet portion (21,22; 62,63) two passes at least (24,25 that is communicated with said export department (23,64); 65,66), and these passages (24,25; 65,66) junction surface (26,67) has a central part and a peripheral part, and they are according to concentric pattern configuration;

With a kind of core material (31,71) from a corresponding inlet portion (21,62) one of supply in the aforementioned channels (24,25) of leading to said junction surface (26,27) central portion, simultaneously with a kind of clad material (35,73) supply in another passage (25,66) that leads to peripheral part from corresponding inlet portion (22,63), make these two kinds of materials locate mutual junction at this in said junction surface (26,67);

Squeeze out a kind of formed body (37,75) from aforementioned export department (23,64), the part corresponding with fuse arranged, and around this central portion office the part corresponding with covering arranged at it at its middle body;

Make above-mentioned formed body (37,75) drying;

From then on plant and remove decon in the formed body (37,75);

And

Make solidization of formed body of this final gained.

2, the method for claim 1 is characterised in that: aforesaidly extend the passage (24,65) that is used for supplying with core material (31,71) from said inlet portion (21,62) and get straight form.

3, the method for stating as claimed in claim 2 is characterised in that: described core material (31,71) is the glass bar (31) that mainly contains quartz glass, and clad material (35,73) then is one to contain the plastic material of quartz glass powder.

4, method as claimed in claim 3 is characterised in that: above-mentioned glass bar (31) is that a tree name CVD method makes.

5, method as claimed in claim 3 is characterised in that: aforementioned glass bar (31) has a part of clad material that is formed on its outer peripheral face.

6, method as claimed in claim 2 is characterised in that: core material and clad material both are formed by the plastic material that contains quartz glass powder.

7, the method for claim 1 is characterised in that: by the angle that axis defined of the axis of the inlet portion (21,62) of supplying with core material and the inlet portion (22,63,82,83) of supplying with clad material less than 90 °.

8, the method for claim 1 is characterised in that: the diameter of said export department (23,64) is variable in the aforementioned extrusion equipment.

9, method as claimed in claim 8, be characterised in that: in aforementioned export department (23,64) interior perimeter surface is provided with distensible annular die component (91), be used for making mould spare (91) can radially shrink and the head tank (93) that expands and on the outer peripheral face of this mould spare (91), be provided with one, change the diameter of export department (23,64) thus.

10, the method for claim 1 is characterised in that: aforesaid removing step comprises removing from say the formed body that reaches removes bonding agent and purifies this formed body.

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