阅读说明：本技术 高掺杂掺稀土光纤预制棒的制备方法及光纤预制棒 (The preparation method and preform of highly doped rare-earth-doped fiber precast rod ) 是由 朱侨 罗文勇 杜城 张涛 柯一礼 余远 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种高掺杂掺稀土光纤预制棒及制备方法,该方法包括如下步骤：采用MCVD气相掺杂工艺,在石英基管内反向沉积含有共掺剂的二氧化硅疏松层；采用MCVD气相掺杂工艺,在所述二氧化硅疏松层上反向沉积稀土离子；通氧正向烧结,完成一趟稀土掺杂层的沉积；重复多趟稀土掺杂层的沉积,进行成棒处理,得到光纤预制棒。本发明将共掺剂沉积过程与稀土离子沉积过程分离,且共掺剂沉积得到疏松层,通过疏松层的吸附原理以使得共掺剂与稀土离子均匀混合,不仅可以解决现有技术中稀土离子掺杂不均的问题,而且可以在不改变稀土离子载气流量和高温蒸发系统加热温度的前提下,提高稀土离子在沉积过程中的掺杂效率和掺杂浓度。(The invention discloses a kind of highly doped rare-earth-doped fiber precast rod and preparation methods, and this method comprises the following steps: using MCVD gas phase doping technique, reversely deposition contains the silica weaker zone for being co-doped with agent in quartzy base tube；Using MCVD gas phase doping technique, rare earth ion is reversely deposited on the silica weaker zone；Logical oxygen forward direction sintering, completes the deposition of a rare earth-doped layers；The deposition of more times rare earth-doped layers is repeated, progress is handled at stick, obtains preform.The present invention will be co-doped with agent deposition process and separate with rare earth ion deposition process, and it is co-doped with agent and deposits to obtain weaker zone, it is uniformly mixed so that being co-doped with agent with rare earth ion by the absorption principle of weaker zone, it not only can solve the problem of rare earth ion doped unevenness in the prior art, and rare earth ion doping efficiency during the deposition process and doping concentration can be improved under the premise of not changing rare earth ion carrier gas flux and high temperature evaporation system heating temperature.)

1. a kind of preparation method of highly doped rare-earth-doped fiber precast rod, which is characterized in that it includes the following steps:

Using MCVD gas phase doping technique, reversely deposition contains the silica weaker zone for being co-doped with agent in quartzy base tube；

Using MCVD gas phase doping technique, rare earth ion is reversely deposited on the silica weaker zone；

Logical oxygen forward direction sintering, completes the deposition of a rare earth-doped layers；

Repeat the deposition of more times rare earth-doped layers；

It carries out into stick to handle, obtains preform.

2. the preparation method of highly doped rare-earth-doped fiber precast rod as described in claim 1, it is characterised in that: described to be co-doped with agent Including aluminium.

3. the preparation method of highly doped rare-earth-doped fiber precast rod as claimed in claim 2, it is characterised in that: the aluminium is corresponding Alchlor carrier gas flux be 100~250sccm.

4. the preparation method of highly doped rare-earth-doped fiber precast rod as claimed in claim 2, it is characterised in that: described to be co-doped with agent It further include at least one of phosphorus, germanium, fluorine and cerium.

5. the preparation method of highly doped rare-earth-doped fiber precast rod as claimed in claim 4, it is characterised in that:

When it is described be co-doped with agent and include phosphorus when, the carrier gas flux of the corresponding phosphorus oxychloride of phosphorus is 100~300sccm；

When it is described be co-doped with agent and include germanium when, the carrier gas flux of the corresponding germanium tetrachloride of germanium is 100~250sccm；

When it is described be co-doped with agent and include fluorine when, the carrier gas flux of the corresponding perfluoroethane of fluorine is 50~100sccm；

When it is described be co-doped with agent and include cerium when, the carrier gas flux of the corresponding cerium chelate of cerium is 50~100sccm.

6. the preparation method of highly doped rare-earth-doped fiber precast rod as described in claim 1, it is characterised in that: the rare earth from The carrier gas flux of the corresponding Rare Earth Chelate of son is 300~1000sccm.

7. the preparation method of highly doped rare-earth-doped fiber precast rod as described in claim 1, it is characterised in that: the rare earth from Attached bag includes at least one of ytterbium, thulium, erbium.

8. highly doped rare-earth-doped fiber precast rod as claimed in claim 7, which is characterized in that the doping of the rare earth ion is dense Degree is calculated according to its oxide form:

When the rare earth ion includes ytterbium, the doping concentration of ytterbium is 0.4~1.0mol%；

When the rare earth ion includes thulium, the doping concentration of thulium is 0.3~0.8mol%；

When the rare earth ion includes erbium, the doping concentration of erbium is 0.4~1.0mol%.

9. a kind of highly doped rare-earth-doped fiber precast rod prepared using method as described in any of the claims 1 to 8.

10. highly doped rare-earth-doped fiber precast rod as claimed in claim 9, it is characterised in that: the preform includes The sandwich layer and quartz layer being sequentially distributed from inside to outside, the quartz layer are made of the quartzy base tube, and the sandwich layer is by all times Rare earth-doped layers constitute, and the numerical aperture NA of the sandwich layer be 0.05~0.30.

Technical field

The present invention relates to optic fibre manufacturing technology fields, and in particular to a kind of preparation side of highly doped rare-earth-doped fiber precast rod Method and preform.

Background technique

Rare earth doped fiber is a kind of important Active Optical Fiber.Rare earth doped fiber refer to mixed in the fibre core of conventional fiber it is micro- Measure rare earth element (such as ytterbium, erbium), facilitate passively transmission fiber be changed into the Active fiber with amplifying power.Mix rare earth light Fibre can be used for manufacturing fiber amplifier and optical fiber laser.

By taking Yb dosed optical fiber as an example, as the gain media of laser, Yb dosed optical fiber can convert pump light to laser, and From the laser output for realizing laser.Compared to solid state laser and gas laser, optical fiber laser is that beam quality is best Laser form, optical fiber laser is substantially the laser for the pumping laser of low beam quality being converted to more high light beam quality Output, due to the continuous extension of application field, also constantly promotes the demand of optical fiber laser output power, optical fiber laser Output power by several hundred milliwatts rise to tens watts even several hectowatts, and start in the civil field such as optic communication, printing, medical treatment It is applied.

Er-doped fiber is the key that the wide band super fluorescence Er-Doped superfluorescent fiber source (SFS) that high-precision optical fiber gyro (FOG) is used Component.In space technology, the internal monitoring of nuclear reactor radioactive source, submarine communication and have the various of Antiradiation ability Fortification and traffic guidance place etc. have biggish potential demand, have more wide application prospect.

Traditional rare earth doped fiber generally takes MCVD liquid phase doping methods to prepare, and there is can not make big core for this method The disadvantages of diameter prefabricated rods, process repeatability and uniform doping are poor and cumbersome.

Compared to the MCVD liquid phase doping methods of above-mentioned use, it has been found that MCVD gas phase doping method passes through carrier gas at high temperature Volatile Rare Earth Chelate steam is delivered directly in reaction tube, and with remaining be co-doped with agent together with deposit, have operation Easy, the advantages that uniform doping is good, technique reproducibility is high, thus, MCVD gas phase doping method just gradually becomes by favor The preparation method of rare-earth-doped fiber precast rod.

However, the MCVD gas phase doping method of above-mentioned use, in actually rod motion processed, rare earth ion doped inefficiency, As the doping efficiency of ytterbium ion only has 3%, doping concentration 0.2mol%, thus high-concentration dopant relatively difficult to achieve.And if it is desired to The doping concentration of rare earth ion is further increased, can be realized using two ways:

First, the method for improving the heating temperature of rare earth ion volatilization system can be used, but existing for this method Drawback is the rare earth ion steam blocking easy to form in the duct of high concentration, to damage to equipment.

Second, can be using the method for improving carrier gas flux, although improving carrier gas flux can be improved mixing for rare earth ion Miscellaneous concentration, but the carrier gas meeting of big flow is so that rare earth ion is reduced in the longitudinal distributing homogeneity of prefabricated rods, to reduce Available stick is long.

In addition to this, although both the above method can improve the doping concentration of rare earth ion in prefabricated rods, simultaneously Do not solve the problems, such as rare earth ion doped low efficiency fundamentally.Therefore, in order to be able to achieve the doping of higher concentration, it would be highly desirable to occur A kind of process effectively improving rare earth ion doped efficiency.

Summary of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a kind of highly doped rare earth doped fiber is prefabricated The preparation method of stick can effectively solve the problems, such as rare earth ion doped unevenness.

To achieve the above objectives, the technical solution adopted by the present invention is that: a kind of system of highly doped rare-earth-doped fiber precast rod Preparation Method comprising following steps:

Using MCVD gas phase doping technique, reversely deposition contains the silica weaker zone for being co-doped with agent in quartzy base tube；

Using MCVD gas phase doping technique, rare earth ion is reversely deposited on the silica weaker zone；

Logical oxygen forward direction sintering, completes the deposition of a rare earth-doped layers；

Repeat the deposition of more times rare earth-doped layers；

It carries out into stick to handle, obtains preform.

It is further, described that be co-doped with agent include aluminium.

Further, the carrier gas flux of the corresponding alchlor of the aluminium is 100~250sccm.

It is further, described that be co-doped with agent further include at least one of phosphorus, germanium, fluorine and cerium.

Further, when it is described be co-doped with agent and include phosphorus when, the carrier gas flux of the corresponding phosphorus oxychloride of phosphorus is 100~ 300sccm；

When it is described be co-doped with agent and include germanium when, the carrier gas flux of the corresponding germanium tetrachloride of germanium is 100~250sccm；

When it is described be co-doped with agent and include fluorine when, the carrier gas flux of the corresponding perfluoroethane of fluorine is 50~100sccm；

When it is described be co-doped with agent and include cerium when, the carrier gas flux of the corresponding cerium chelate of cerium is 50~100sccm.

Further, the carrier gas flux of the corresponding Rare Earth Chelate of the rare earth ion is 300~1000sccm.

Further, the rare earth ion includes at least one of ytterbium, thulium, erbium.

Further, the doping concentration of the rare earth ion is calculated according to its oxide form:

When the rare earth ion includes ytterbium, the doping concentration of ytterbium is 0.4~1.0mol%；

When the rare earth ion includes thulium, the doping concentration of thulium is 0.3~0.8mol%；

When the rare earth ion includes erbium, the doping concentration of erbium is 0.4~1.0mol%.

The present invention also provides a kind of highly doped rare-earth-doped fiber precast rods prepared using the above method.

Further, the preform includes the sandwich layer and quartz layer being sequentially distributed from inside to outside, the quartz layer It is made of the quartzy base tube, the sandwich layer is made of all times rare earth-doped layers, and the numerical aperture NA of the sandwich layer is 0.05~0.30.

Compared with the prior art, the advantages of the present invention are as follows:

In preparation method provided by the invention, each time deposition in MCVD gas phase doping technique is split into independent Two steps deposit to obtain the silica weaker zone containing agent is co-doped in the first step, and second step deposits on silica weaker zone Rare earth ion, and in deposition of rare-earth ion on silica weaker zone, silica weaker zone does not carry out logical oxygen sintering Or without carrying out vitrifying, but lead to oxygen sintering again after completing all times depositions, the advantage of doing so is that: if titanium dioxide Silicon weaker zone carries out logical oxygen sintering or carries out vitrifying, then silica weaker zone can be become to solid layer, then in solid layer When deposition of rare-earth ion, rare earth ion can be only deposited in solid layer surface, it is difficult to enter solid layer in so that rare earth ion with It is co-doped with agent to be difficult to be uniformly mixed, if continuing only to obtain being co-doped with agent and one layer one of rare earth ion using more times depositions in this way The structure that layer is alternately accumulated, this depositional mode is such as " microdeposit-layer upon layer " process；And method of the invention is used, by Logical oxygen sintering is not carried out in silica weaker zone or does not carry out vitrifying, and there are more in silica weaker zone Hole, when deposition of rare-earth ion, silica weaker zone can adsorb rare earth ion and enter among these holes, so that being co-doped with Agent can be mixed uniformly with rare earth ion, and this mode is such as " deposition silica weaker zone-absorption " process.

Preparation method provided by the invention will be co-doped with agent deposition process and separate with rare earth ion deposition process, and it is heavy to be co-doped with agent Product obtains silica weaker zone, is uniformly mixed so that being co-doped with agent with rare earth ion by the absorption principle of silica weaker zone It closes, not only can solve the problem of rare earth ion doped unevenness in the prior art, but also rare earth ion carrier gas can not changed Under the premise of flow and high temperature evaporation system heating temperature, improves the doping efficiency of rare earth ion during the deposition process and doping is dense Degree.Since doping efficiency is improved, the generation of waste material is relatively reduced, while also reducing the cost of manufacture of prefabricated rods.

In preparation method provided by the invention, MCVD gas phase doping technique is used, each Doped ions are directly in gas phase Hybrid concurrency life, which aoxidizes, and deposition reaction is so that deposition uniformity is good in atmosphere can be effectively prevented from MCVD liquid phase doping work It is generally existing due to the problems such as bright spot caused by adulterating unevenly and cluster in skill.

Detailed description of the invention

Fig. 1 is Yb dosed optical fiber end structure illustration provided in an embodiment of the present invention；

Fig. 2 is Yb dosed optical fiber precast rod refractivity Soil profile figure provided in an embodiment of the present invention；

Fig. 3 is Doped ions concentration profile on Yb dosed optical fiber end face provided in an embodiment of the present invention；

Fig. 4 is ytterbium cerium co-doped fiber end structure illustration provided in an embodiment of the present invention；

Fig. 5 is ytterbium cerium co-doped fiber precast rod refractivity Soil profile figure provided in an embodiment of the present invention；

Fig. 6 is Doped ions concentration profile on ytterbium cerium co-doped fiber end face provided in an embodiment of the present invention；

Fig. 7 is Er-doped fiber structural schematic diagram provided in an embodiment of the present invention；

Fig. 8 is Er-doped fiber precast rod refractivity Soil profile figure provided in an embodiment of the present invention；

Fig. 9 is Doped ions concentration profile on Er-doped fiber end face provided in an embodiment of the present invention.

In figure: 1, sandwich layer；2, silica clad；3, inner coating；4, external coating.

Specific embodiment

Invention is further described in detail with reference to the accompanying drawings and embodiments.

First embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod comprising such as Lower step:

S1: using MCVD gas phase doping technique, and reversely deposition is loose containing the silica for being co-doped with agent in quartzy base tube Layer；

S2: MCVD gas phase doping technique is used, 5~10min of rare earth ion is reversely deposited on silica weaker zone；

S3: logical oxygen forward direction sintering, every time sintering lasts 8~15min, to complete the deposition of a rare earth-doped layers；

S4: repeating the deposition of more times rare earth-doped layers, and progress is handled at stick, to obtain preform, handled at stick Step includes being melt into solid bar.

It is forward direction with carrier gas flow direction in preparation method provided in this embodiment, reversed deposition should be understood as depositing Process Flame moving direction is opposite with carrier gas flow direction.

In preparation method provided in this embodiment, MCVD gas phase doping technique is used, each Doped ions are directly in gas Hybrid concurrency life, which aoxidizes, and deposition reaction is so that deposition uniformity is good in phase atmosphere can be effectively prevented from MCVD liquid phase doping It is generally existing due to the problems such as bright spot caused by adulterating unevenly and cluster in technique.

In preparation method provided in this embodiment, each time deposition in MCVD gas phase doping technique is split into independence Two steps, deposit to obtain the silica weaker zone containing agent is co-doped in the first step, second step sinks on silica weaker zone Product rare earth ion, and in deposition of rare-earth ion on silica weaker zone, silica weaker zone does not carry out logical oxygen and burns Knot or no progress vitrifying, but lead to oxygen again after completing all times depositions and be sintered, the advantage of doing so is that: if dioxy SiClx weaker zone carries out logical oxygen sintering or carries out vitrifying, then silica weaker zone can be become to solid layer, then in solid layer When upper deposition of rare-earth ion, rare earth ion can be only deposited in solid layer surface, it is difficult to be entered in solid layer, so that rare earth ion It is difficult to be uniformly mixed with agent is co-doped with, if continuing only to obtain being co-doped with agent and one layer of rare earth ion using more times depositions in this way One layer of structure alternately accumulated, this depositional mode is such as " microdeposit-layer upon layer " process；And method of the invention is used, Since silica weaker zone does not carry out logical oxygen sintering or does not carry out vitrifying, there are more in silica weaker zone Hole, when deposition of rare-earth ion, silica weaker zone can adsorb rare earth ion among these holes, so that altogether Mixing agent can uniformly mix with rare earth ion, and this mode is such as " deposition silica weaker zone-absorption " process.

Therefore, preparation method provided in this embodiment will be co-doped with agent deposition process and separate with rare earth ion deposition process, and Agent is co-doped with to deposit to obtain silica weaker zone, by the absorption principle of silica weaker zone so that be co-doped with agent and rare earth from Sub uniformly mixing, not only can solve the problem of rare earth ion doped unevenness in the prior art, but also can not change rare earth Under the premise of ion carrier flow and high temperature evaporation system heating temperature, the doping efficiency of rare earth ion during the deposition process is improved And doping concentration.Since doping efficiency is improved, the generation of waste material is relatively reduced, while also reducing the system of prefabricated rods Make cost.

Second embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod, the present embodiment Difference with one embodiment is: being co-doped with agent includes aluminium, and the carrier gas flux of the corresponding alchlor of aluminium is 100~ 250sccm。

When depositing silica weaker zone, the carrier gas flux of silicon tetrachloride is 100~250sccm；

It of courses, being co-doped with agent further includes at least one of phosphorus, germanium, fluorine and cerium, in which:

When being co-doped with agent comprising phosphorus, the carrier gas flux of the corresponding phosphorus oxychloride of phosphorus is 100~300sccm；

When being co-doped with agent comprising germanium, the carrier gas flux of the corresponding germanium tetrachloride of germanium is 100~250sccm；

When being co-doped with agent comprising fluorine, the carrier gas flux of the corresponding perfluoroethane of fluorine is 50~100sccm；

When being co-doped with agent comprising cerium, the carrier gas flux of the corresponding cerium chelate of cerium is 50~100sccm.

The carrier gas flux of the corresponding Rare Earth Chelate of rare earth ion is 300~1000sccm.

Third embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod, the present embodiment Difference with one embodiment is: rare earth ion includes at least one of ytterbium, thulium, erbium.

Wherein, the doping concentration of rare earth ion is calculated according to its oxide form:

When rare earth ion includes ytterbium, the doping concentration of ytterbium is 0.4~1.0mol%；

When rare earth ion includes thulium, the doping concentration of thulium is 0.3~0.8mol%；

When rare earth ion includes erbium, the doping concentration of erbium is 0.4~1.0mol%.

Four embodiment of the invention provides a kind of using the highly doped doped rare earth light prepared such as any of the above-described method Fine prefabricated rods, preform include the sandwich layer and quartz layer being sequentially distributed from inside to outside, and quartz layer is made of quartzy base tube, core Layer is made of all times rare earth-doped layers, and the numerical aperture NA of sandwich layer is 0.05~0.30.Above-mentioned optical fiber is completed in preparation After prefabricated rods, usually preform is embedded in quartz socket tube, quartz socket tube and above-mentioned quartz layer is made to collectively form quartzy packet Layer, in the present embodiment, silica clad sectional area is 100~500mm²。

Below by way of the present invention is explained in detail by three specific embodiments again.

Fifth embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod comprising such as Lower step:

S1: MCVD gas phase doping technique, the silica weaker zone that reversed deposition of aluminum phosphorus is co-doped in quartzy base tube are used； Wherein, the carrier gas flux of silicon tetrachloride is 200sccm, and the carrier gas flux of phosphorus oxychloride is 150sccm, the carrier gas stream of alchlor Amount is 200sccm；

S2: MCVD gas phase doping technique is used, ytterbium ion, the load of ytterbium chelate are reversely deposited on silica weaker zone Throughput is 500~800sccm；Depositing temperature in step S1 and S2 is set as 1850 DEG C；

S3: logical oxygen forward direction sintering, when sintering a length of 10min, complete the deposition of a rare earth-doped layers；

S4: the deposition of more times rare earth-doped layers is repeated, solid bar is melt into, obtains preform；

S5: grinding for octagon quartz socket tube is carried out, by preform, calculates and is reached required for corresponding quartz socket tube The size arrived makes quartz socket tube according to the dimensioned；Preform is embedded in quartz socket tube, wire drawing obtains mixing ytterbium light It is fine.

It is (rear-earth-doped by all times to be followed successively by sandwich layer 1 from inside to outside for Yb dosed optical fiber end view as shown in Figure 1 Layer is constituted), silica clad 2 (being made of quartzy base tube and quartz socket tube), inner coating 3 and external coating 4, wherein inner coating 3 uses Low-refraction coating, external coating 4 use high-temperature resistant coating, and the cross-sectional area of octagon quartz socket tube is 406mm²。

After the production for completing Yb dosed optical fiber, weighs to remaining ytterbium Yb/ aluminium Al raw material, obtain ytterbium Yb consumption of raw materials 9.8g, aluminium Al consumption of raw materials 19.2g, the molar ratio of aluminium Al/ ytterbium Yb consumption are 14.31.

In the present embodiment, by controlling the carrier gas flux of Al, Yb, Al consumption of raw materials amount and Yb after stick processed every time are kept The molar ratio of consumption of raw materials amount 10 or more, thus guarantee in prefabricated rods Al/Yb concentration molar ratio 7 or more, with ensure Yb from The good dispersibility of son.

The Yb dosed optical fiber transparent and homogeneous that the preparation process obtains shows ytterbium favorable dispersibility without precipitation.

Yb dosed optical fiber precast rod refractivity Soil profile figure as shown in Figure 2,1 refractive index profile of sandwich layer is smooth, shows this The uniform doping of ytterbium is good in Yb dosed optical fiber prefabricated rods.Doped ions concentration profile as shown in Figure 3, ytterbium in Yb dosed optical fiber Doping concentration 0.5mol%, be higher than 0.2mol%, the average doping concentration of aluminium is 4.2mol%, and the average doping concentration of phosphorus is 5.2mol%, aluminium/ytterbium doping concentration ratio are 8.2.It is calculated according to doping concentration and consumption, ytterbium doping efficiency is 9% or so, far Higher than 3%.The Yb dosed optical fiber typical index drawn is shown in Table 1.

Yb dosed optical fiber key index prepared by table 1

Operation wavelength (light out)	1060~1115nm
		915 absorption coefficients	1.50±0.10
1 diameter of sandwich layer	11±1μm
		1 numerical aperture of sandwich layer	0.070±0.010
3 numerical aperture of inner coating	≥0.46
		2 diameter of silica clad	128±2μm

Sixth embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod comprising such as Lower step:

S1: using MCVD gas phase doping technique, and the silica that reversed deposition of aluminum-cerium-fluorine is co-doped in quartzy base tube is dredged Loose layer；Wherein, the carrier gas flux of silicon tetrachloride is 220sccm, and the carrier gas flux of perfluoroethane is 80sccm, the load of alchlor Throughput is 200sccm, and the carrier gas flux of cerium chelate is 90sccm；

S2: MCVD gas phase doping technique is used, ytterbium ion, the load of ytterbium chelate are reversely deposited on silica weaker zone Throughput is 500~800sccm；Depositing temperature in step S1 and S2 is set as 1850 DEG C；

S3: logical oxygen forward direction sintering, when sintering a length of 10min, to complete the deposition of a rare earth-doped layers；

S4: the deposition of more times rare earth-doped layers is repeated, solid bar is melt into, obtains preform；

S5: grinding for octagon quartz socket tube is carried out, by preform, calculates and is reached required for corresponding quartz socket tube The size arrived makes quartz socket tube according to the dimensioned；Preform is embedded in quartz socket tube, it is total that wire drawing obtains ytterbium cerium Mix optical fiber.

Ytterbium cerium co-doped fiber end structure illustration as shown in Figure 4, be followed successively by from inside to outside sandwich layer 1, silica clad 2, Inner coating 3 and external coating 4, wherein inner coating 3 uses low-refraction coating, and external coating 4 uses high-temperature resistant coating.Octagon stone The cross-sectional area of English casing is 138mm²。

After the production for completing preform, weighs to remaining ytterbium Yb/ aluminium Al raw material, obtain ytterbium Yb consumption of raw materials 10.8g, aluminium Al consumption of raw materials 22.2g, the molar ratio of aluminium Al/ ytterbium Yb consumption are 12.25.

The ytterbium cerium co-doped fiber transparent and homogeneous that the preparation process obtains shows ytterbium favorable dispersibility without precipitation.

Ytterbium cerium co-doped fiber precast rod refractivity Soil profile figure as shown in Figure 5,1 refractive index profile of sandwich layer is smooth, table The uniform doping of ytterbium is good in the bright ytterbium cerium co-doped fiber prefabricated rods.Doped ions concentration profile as shown in FIG. 6, ytterbium cerium Ytterbium doping concentration is 0.6mol% in co-doped fiber, and aluminium average doping concentration is 5.2mol%, and aluminium/ytterbium doping concentration ratio is 8.7； Cerium average doping concentration 0.12%, F average doping concentration are 1.2%.It is calculated according to doping concentration and consumption, ytterbium doping efficiency It is 10% or so, is much higher than 3%.The ytterbium cerium co-doped fiber typical index drawn is shown in Table 2.

Table, the ytterbium cerium co-doped fiber key index of 2 preparations

Operation wavelength (light out)	1060~1115
		915 absorption coefficients	2.35±0.30dB/m
1 diameter of sandwich layer	20±1.2μm
		1 numerical aperture of sandwich layer	0.080±0.005
3 numerical aperture of inner coating	≥0.46
		2 diameter of silica clad	128±2μm

Seventh embodiment of the invention provides a kind of preparation method of highly doped rare-earth-doped fiber precast rod comprising such as Lower step:

S1: using MCVD gas phase doping technique, and the silica that reversed deposition of aluminum-phosphorus-germanium is co-doped in quartzy base tube is dredged Loose layer；Wherein, the carrier gas flux of silicon tetrachloride is 200sccm, and the carrier gas flux of phosphorus oxychloride is 150sccm, alchlor Carrier gas flux is 200sccm, and the carrier gas flux of germanium tetrachloride is 126sccm；

S2: MCVD gas phase doping technique is used, erbium ion, the load of erbium chelate are reversely deposited on silica weaker zone Throughput is 600sccm；Depositing temperature in step S1 and S2 is set as 1850 DEG C；

S3: logical oxygen forward direction sintering, when sintering a length of 12min, complete the deposition of a rare earth-doped layers；

S4: the deposition of more times rare earth-doped layers is repeated, solid bar is melt into, obtains preform；

S5: grinding for octagon quartz socket tube is carried out, by preform, calculates and is reached required for corresponding quartz socket tube The size arrived makes quartz socket tube according to the dimensioned；Preform is embedded in quartz socket tube, wire drawing obtains er-doped light It is fine；

Optical fiber structure schematic diagram as shown in Figure 7 is followed successively by sandwich layer 1, silica clad 2, external coating 4, outer painting from inside to outside Layer 4 has high-strength multifunctional characteristic, Er-doped fiber precast rod refractivity Soil profile figure as shown in Figure 8,1 refractive index of sandwich layer Section is smooth, shows that the uniform doping of erbium in the Er-doped fiber is good.Doped ions concentration profile shown in Figure 9, Er ions concentration 0.45mol%.The Er-doped fiber typical index drawn is shown in Table 3.

Er-doped fiber key index prepared by table 3

Operation wavelength (light out)	1530~1565nm
		980 absorption coefficients	5.2±2.5dB/m
1 numerical aperture of sandwich layer	0.23±0.02
		1 mode field diameter of sandwich layer	5.6±0.7μ[email protected]
2 diameter of silica clad	125±2μm

The present invention is not limited to the above-described embodiments, for those skilled in the art, is not departing from Under the premise of the principle of the invention, several improvements and modifications can also be made, these improvements and modifications are also considered as protection of the invention Within the scope of.The content being not described in detail in this specification belongs to the prior art well known to professional and technical personnel in the field.