阅读说明：本技术 一种改善光纤衰减均匀性的生产工艺 (Production process for improving attenuation uniformity of optical fiber ) 是由 张玉棋 张学军 王强强 章海峰 吴志元 刘世浩 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种改善光纤衰减均匀性的生产工艺,属于光纤技术领域,包括如下步骤：通过多点测试得到满足配方生长要求的芯棒提升速度与喷灯角度关系；将芯棒通过三抓卡盘固定在石英腔体内,将氢气和氧气通入喷灯,并在石英腔体内点燃,对反应腔体和芯棒预热；将SiCl4和GeCl4原料气体经喷灯送入氢氧焰中,预制棒开始生长；通过激光接收器接收到的激光功率变化,确定预制棒的直径变化,从而实时控制芯棒的提升速度和喷灯的角度,确保预制棒均匀生长,从而改善光纤衰减均匀性；预制棒生长结束后,喷灯先停止SiCl4和GeCl4原料气体的供入,然后停止氢气和氧气的供应,待石英腔体内温度自然降低至室温后开启石英腔体并取出预制棒。(The invention discloses a production process for improving the attenuation uniformity of an optical fiber, which belongs to the technical field of optical fibers and comprises the following steps: obtaining the relation between the lifting speed of the core rod and the angle of the blast burner, which meets the growth requirement of the formula, through a multipoint test; fixing a core rod in a quartz cavity through a three-grab chuck, introducing hydrogen and oxygen into a blast burner, igniting the hydrogen and the oxygen in the quartz cavity, and preheating the reaction cavity and the core rod; feeding SiCl4 and GeCl4 raw material gas into oxyhydrogen flame through a blast burner, and starting the growth of the prefabricated rod; the diameter change of the prefabricated rod is determined through the laser power change received by the laser receiver, so that the lifting speed of the core rod and the angle of a blast burner are controlled in real time, the prefabricated rod is ensured to grow uniformly, and the attenuation uniformity of the optical fiber is improved; after the preform is grown, the torch stops the supply of the raw material gases of SiCl4 and GeCl4, then stops the supply of hydrogen and oxygen, and opens the quartz cavity after the temperature in the quartz cavity naturally drops to room temperature and takes out the preform.)

1. A production process for improving the attenuation uniformity of an optical fiber is characterized by comprising the following steps:

s1, determining growth speed relation

Fixing a core rod in a quartz cavity through a three-grab chuck, keeping the lifting speed of the core rod constant, adjusting the included angle theta between a blowtorch and the axis of the core rod to enable the growth diameter of the prefabricated rod to meet the requirement of a formula, accelerating the lifting speed, adjusting the included angle between the blowtorch and the axis of the core rod again to enable the growth diameter of the prefabricated rod to meet the requirement of the formula, and obtaining the relation between the lifting speed of the core rod and the angle of the blowtorch which meets the requirement of the formula growth through multi-point testing;

s2 preheating of mandrel installation

Fixing a core rod in a quartz cavity through a three-grab chuck, lowering the core rod through a lifting mechanism to align the bottom of the core rod with a laser line, adjusting the angle of a blowtorch to enable the axis of the blowtorch to intersect with the axis of the core rod and the center of a circle at the bottom of the core rod, introducing hydrogen and oxygen into the blowtorch, igniting the hydrogen and the oxygen in the quartz cavity, generating oxyhydrogen flame with the temperature of 900 plus 1000 ℃, and preheating the reaction cavity and the core rod;

s3 preform growth

Sending SiCl4 and GeCl4 raw material gas into oxyhydrogen flame through a blast burner to perform hydrolysis reaction, and depositing SiO2 and GeO2 powder generated by oxidation at the lower end of a core rod due to thermophoretic motion to form a core layer of a prefabricated rod; simultaneously, introducing SiCl4 raw material gas into a blast burner to enter oxyhydrogen flame, leading the gas to generate hydrolysis reaction, and depositing SiO2 powder generated by oxidation around a core layer to form an optical cladding of a prefabricated rod;

s4, growth control

S401, according to the diameter of the prefabricated rod to be produced, irradiating laser on a prefabricated rod standard component with the same diameter, receiving the laser through a laser receiver to obtain laser power a, determining a as the standard laser transmittance, and setting a control parameter b and a limiting parameter c;

s402, when the laser transmittance is a + b, reducing the lifting speed of the core rod by the lifting mechanism, and simultaneously driving the blowtorch to move in the direction of high deposition rate by the adjusting mechanism, namely reducing theta so that the theta and the lifting speed of the core rod meet the relation between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is a-b, the lifting mechanism increases the lifting speed of the core rod, and the adjusting mechanism drives the blowtorch to move in the direction of low deposition rate, namely theta is increased, so that theta and the lifting speed of the core rod meet the relationship between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is a + c, the lifting mechanism carries the core rod to grow upwards at a fixed slow speed;

when the laser transmittance is a-c, the lifting mechanism carries the core rod to fix and rapidly grow upwards;

s5, preform ending

After the preform is grown, the torch stops the supply of the raw material gases of SiCl4 and GeCl4, then stops the supply of hydrogen and oxygen, and opens the quartz cavity after the temperature in the quartz cavity naturally drops to room temperature and takes out the preform.

2. The process of claim 1, wherein the step of applying the optical fiber comprises: the core rod is always in a rotating state, the rotating speed of the core rod is 15-25r/min, and the lifting speed is 40-70 mm/h.

3. The process of claim 1, wherein the step of applying the optical fiber comprises: the quartz cavity is internally provided with negative pressure, and the negative pressure is 40-50 Pa.

4. The process of claim 1, wherein the step of applying the optical fiber comprises: in step S401, the limiting parameter is b/100-b/10; in step S402, the preform growth rate S ═ xa, where x is the preform optimum rate growth coefficient, when the laser transmittance is a + b, S ═ xa (a + b), when the laser transmittance is a-b, S ═ xa (a-b), when the laser transmittance is a + c, S is a fixed rate less than xa, and when the laser transmittance is a-c, S is a fixed rate greater than xa.

5. The process of claim 1, wherein the step of applying the optical fiber comprises: s1 step S5 used equipment includes cavity (1) and last cavity (2) down, cavity (1) and last cavity (2) integrated into one piece down form the quartz cavity, it has operation mouth (3) to go up to open on the outer wall of cavity (2) and lower cavity (1), installation door (4) that opens and shuts on operation mouth (3), it grabs chuck (5) to be equipped with three in last cavity (2), the top fixed mounting motor case (6) of chuck (5) are grabbed to three, first motor (7) of fixed mounting in motor case (6), chuck (5) are grabbed to three in the output shaft fixed connection of first motor (7), install hoist mechanism (8) between the roof of motor case (6) and last cavity (2), one side outer wall fixed mounting laser emitter (10) of cavity (1) down, cavity (1) is just to the outer wall fixed mounting laser receiver (11) of laser emitter (10) down, the bottom inner wall of lower cavity (1) installs blast burner (14), installation adjustment mechanism (9) between blast burner (14) and lower cavity (1).

6. The process of claim 5, wherein the step of applying the optical fiber attenuation is further characterized by: go up cavity (2) and be internal diameter 400mm, high 2000 mm's hollow circular cylinder structure, one side that blowtorch (14) were kept away from in cavity (1) down is fixed to be cup jointed blast pipe (12), the outer wall of going up cavity (2) is fixed to be cup jointed air supplement pipe (13).

7. The process of claim 5, wherein the step of applying the optical fiber attenuation is further characterized by: lifting mechanism (8) include mount pad (83), fixed mounting (83) on last cavity (2), the one end of the top both sides fixed connection guide bar (81) of motor case (6), once of top surface middle part fixed connection double-screw bolt (82) of motor case (6), the other end of guide bar (81) and double-screw bolt (82) all slides and runs through cavity (2) and mount pad (83), nut cover (86) are cup jointed in mount pad (83) internal rotation, nut cover (86) cup joint double-screw bolt (82) through the helicitic texture, the outer wall fixed cup joint ring gear (87) of nut cover (86), the top fixed mounting second motor (84) of mount pad (83), output shaft fixed connection gear (85) of second motor (84), gear (85) meshing ring gear (87).

8. The process of claim 5, wherein the step of applying the optical fiber attenuation is further characterized by: adjustment mechanism (9) are including revolving chute (96), one side of cavity (1) is opened down has revolving chute (96), it cup joints pivot (91) to rotate between revolving chute (96), fixed cup joint worm wheel (92) on pivot (91), one side fixed mounting blast burner (14) of the inner wall of cavity (1) are close to down in worm wheel (92), outer wall fixed mounting fixed plate (93) of cavity (1) down, bottom fixed mounting third motor (95) of fixed plate (93), the output shaft of third motor (95) runs through fixed plate (93) and fixed connection worm (94), worm (94) meshing worm wheel (92).

Technical Field

The invention relates to the technical field of optical fibers, in particular to a production process for improving the attenuation uniformity of an optical fiber.

Background

Attenuation is always the most important index in optical fiber preform and optical fiber production, the optical fiber attenuation needs to be controlled through a stable process to improve the optical fiber quality, mode conversion occurs when the optical fiber structure is irregular due to an imperfect control method, part of transmission energy is emitted out of a fiber core to become a radiation mode, and part of loss caused by micro structural fluctuation and non-uniform waveguide structure inside the optical fiber exists on the interface of a core cladding of the optical fiber, so that the loss is increased.

The growth speed in the VAD production process is unstable due to the imperfect control method, people pay attention at any time, the existing control method is to pay attention to the growth diameter of the optical preform artificially, when the artificial diameter changes, the error is large, the lifting of a core rod or the injection amount of a blowtorch is adjusted simply during control and adjustment, the control mode is single, and the size of the optical preform is difficult to stabilize.

Disclosure of Invention

In view of the above-mentioned technical deficiencies, it is an object of the present invention to provide a manufacturing process for improving attenuation uniformity of an optical fiber.

In order to solve the technical problems, the invention adopts the following technical scheme: the invention provides a production process for improving the attenuation uniformity of an optical fiber, which comprises the following steps:

s1, determining growth speed relation

Fixing a core rod in a quartz cavity through a three-grab chuck, keeping the lifting speed of the core rod constant, adjusting the included angle theta between a blowtorch and the axis of the core rod to enable the growth diameter of the prefabricated rod to meet the requirement of a formula, accelerating the lifting speed, adjusting the included angle between the blowtorch and the axis of the core rod again to enable the growth diameter of the prefabricated rod to meet the requirement of the formula, and obtaining the relation between the lifting speed of the core rod and the angle of the blowtorch which meets the requirement of the formula growth through multi-point testing;

s2 preheating of mandrel installation

Fixing a core rod in a quartz cavity through a three-grab chuck, lowering the core rod through a lifting mechanism to align the bottom of the core rod with a laser line, adjusting the angle of a blowtorch to enable the axis of the blowtorch to intersect with the axis of the core rod and the center of a circle at the bottom of the core rod, introducing hydrogen and oxygen into the blowtorch, igniting the hydrogen and the oxygen in the quartz cavity, generating oxyhydrogen flame with the temperature of 900 plus 1000 ℃, and preheating the reaction cavity and the core rod;

s3 preform growth

Sending SiCl4 and GeCl4 raw material gas into oxyhydrogen flame through a blast burner to perform hydrolysis reaction, and depositing SiO2 and GeO2 powder generated by oxidation at the lower end of a core rod due to thermophoretic motion to form a core layer of a prefabricated rod; simultaneously, introducing SiCl4 raw material gas into a blast burner to enter oxyhydrogen flame, leading the gas to generate hydrolysis reaction, and depositing SiO2 powder generated by oxidation around a core layer to form an optical cladding of a prefabricated rod;

s4, growth control

S401, according to the diameter of the prefabricated rod to be produced, irradiating laser on a prefabricated rod standard component with the same diameter, receiving the laser through a laser receiver to obtain laser power a, determining a as the standard laser transmittance, and setting a control parameter b and a limiting parameter c;

s402, when the laser transmittance is a + b, reducing the lifting speed of the core rod by the lifting mechanism, and simultaneously driving the blowtorch to move in the direction of high deposition rate by the adjusting mechanism, namely reducing theta so that the theta and the lifting speed of the core rod meet the relation between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is a-b, the lifting mechanism increases the lifting speed of the core rod, and the adjusting mechanism drives the blowtorch to move in the direction of low deposition rate, namely theta is increased, so that theta and the lifting speed of the core rod meet the relationship between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is a + c, the lifting mechanism carries the core rod to grow upwards at a fixed slow speed;

when the laser transmittance is a-c, the lifting mechanism carries the core rod to fix and rapidly grow upwards;

s5, preform ending

After the preform is grown, the torch stops the supply of the raw material gases of SiCl4 and GeCl4, then stops the supply of hydrogen and oxygen, and opens the quartz cavity after the temperature in the quartz cavity naturally drops to room temperature and takes out the preform.

In a preferred embodiment, the mandrel is always in a rotating state, the rotating speed of the mandrel is 15-25r/min, and the lifting speed is 40-70 mm/h.

In a preferable embodiment, the outer wall of the quartz cavity is provided with exhaust air and air supplement, negative pressure is maintained in the quartz cavity, and the negative pressure is 40-50 Pa.

In a preferred embodiment, in step S401, the limiting parameter is b/100-b/10; in step S402, the preform growth rate S ═ xa, where x is the preform optimum rate growth coefficient, when the laser transmittance is a + b, S ═ xa (a + b), when the laser transmittance is a-b, S ═ xa (a-b), when the laser transmittance is a + c, S is a fixed rate less than xa, and when the laser transmittance is a-c, S is a fixed rate greater than xa.

According to an embodiment of the invention, the used equipment comprises a lower cavity and an upper cavity, the lower cavity and the upper cavity are integrally formed to form a quartz cavity, an operation opening is formed in the outer wall of the upper cavity and the outer wall of the lower cavity, an opening and closing door is installed on the operation opening, a three-grip chuck is arranged in the upper cavity, a motor box fixedly installed at the top of the three-grip chuck is fixedly installed in the motor box, a first motor is fixedly installed in the motor box, the three-grip chuck is fixedly connected with an output shaft of the first motor, a lifting mechanism is installed between the motor box and a top plate of the upper cavity, a laser transmitter is fixedly installed on the outer wall of one side of the lower cavity, the lower cavity is just opposite to a laser receiver fixedly installed on the outer wall of the laser transmitter, a spray lamp is installed on the inner wall of the bottom of the lower cavity, and an adjusting mechanism is installed between the spray lamp and the lower cavity.

In a preferred embodiment, the upper cavity is a hollow cylinder structure with an inner diameter of 400mm and a height of 2000mm, an exhaust pipe is fixedly sleeved on one side of the lower cavity far away from the blast burner, and an air supply pipe is fixedly sleeved on the outer wall of the upper cavity.

Preferably, the lifting mechanism comprises a mounting seat, the mounting seat is fixed on the upper cavity, one end of a guide rod is fixedly connected to two sides of the top of the motor box, once a stud is fixedly connected to the middle of the top surface of the motor box, the other ends of the guide rod and the stud penetrate through the upper cavity and the mounting seat in a sliding mode, a nut sleeve is sleeved in the mounting seat in an internal rotation mode and is sleeved with the stud through a threaded structure, a toothed ring is fixedly sleeved on the outer wall of the nut sleeve, a second motor is fixedly mounted on the top of the mounting seat, a gear is fixedly connected to an output shaft of the second motor, and the gear is meshed with the toothed ring.

In an embodiment of the present invention, the adjusting mechanism includes a rotating groove, the rotating groove is formed in one side of the lower cavity, the rotating groove rotates to sleeve the rotating shaft, a worm wheel is fixedly sleeved on the rotating shaft, a blowtorch is fixedly installed on one side of the inner wall of the lower cavity, the outer wall of the lower cavity is fixedly installed with a fixing plate, a third motor is fixedly installed at the bottom of the fixing plate, an output shaft of the third motor penetrates through the fixing plate and is fixedly connected with a worm, and the worm is engaged with the worm wheel.

The invention has the beneficial effects that:

1. the relationship between the lifting speed of the core rod and the angle of the blast burner, which meets the growth requirement of the formula, is obtained through multi-point testing, so that the growth of the preform is controlled through double regulation of the lifting speed and the angle of the blast burner during growth control, and the comparison with a single control factor is more reliable;

2. the second motor drives the gear to rotate, the gear drives the nut sleeve to rotate through the gear ring, the nut sleeve drives the stud to lift, so that the lifting of the core rod is realized, the change of the lifting speed can be realized by controlling the rotating speed of the second motor, the third motor drives the worm to rotate, and the worm drives the worm wheel to rotate, so that the change of the pitching angle of the blast burner is realized, and the lifting adjustment and the angle adjustment of the blast burner are stable and reliable;

3. in the growth process, the diameter change of the prefabricated rod is determined through the laser power change received by the laser receiver, so that the lifting speed of the core rod and the angle of the blast burner are controlled in real time, the uniform growth of the prefabricated rod is ensured, and the attenuation uniformity of the optical fiber is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a manufacturing process for improving attenuation uniformity of an optical fiber according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the apparatus of the present invention.

Fig. 3 is a schematic view of the internal structure of the upper chamber of the present invention.

FIG. 4 is a schematic cross-sectional view of the present invention.

Fig. 5 is an enlarged view of fig. 3 according to the present invention.

FIG. 6 is a schematic view showing an angle between a burner and a preform according to the present invention.

FIG. 7 is a graph of the relationship between the lift speed of the mandrel and the angle of the torch according to the present invention.

FIG. 8 is a diagram of a test according to an embodiment of the present invention.

Description of reference numerals: 1. a lower cavity; 2. an upper cavity; 3. an operation port; 4. opening and closing the door; 5. a three-grab chuck; 6. a motor case; 7. a first motor; 8. a lifting mechanism; 81. a guide bar; 82. a stud; 83. a mounting seat; 84. a second motor; 85. a gear; 86. a nut sleeve; 87. a toothed ring; 9. an adjustment mechanism; 91. a rotating shaft; 92. a worm gear; 93. a fixing plate; 94. a worm; 95. a third motor; 96. rotating the groove; 10. a laser transmitter; 11. a laser receiver; 12. an exhaust pipe; 13. air supplementing pipes; 14. and (4) blowing a lamp.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b): as shown in fig. 1 to 8, the present invention provides a production process for improving attenuation uniformity of an optical fiber, comprising the following steps:

s1, determining growth speed relation

Fixing a core rod in a quartz cavity through a three-grab chuck, keeping the lifting speed of the core rod constant, adjusting the included angle theta between a blowtorch and the axis of the core rod to enable the growth diameter of the preform rod to meet the requirement of a formula, accelerating the lifting speed, adjusting the included angle between the blowtorch and the axis of the core rod again to enable the growth diameter of the preform rod to meet the requirement of the formula, and obtaining the relation between the lifting speed of the core rod and the angle of the blowtorch which meets the requirement of the formula growth through multi-point testing, as shown in figure 6, so that the growth of the preform rod is controlled through double adjustment of the lifting speed and the angle of the blowtorch during growth control, and the comparison with a single control factor is more reliable;

s2 preheating of mandrel installation

Fixing a core rod in a quartz cavity through a three-grab chuck, lowering the core rod through a lifting mechanism to align the bottom of the core rod with a laser line, adjusting the angle of a blowtorch to enable the axis of the blowtorch to intersect with the axis of the core rod and the center of a circle at the bottom of the core rod, introducing hydrogen and oxygen into the blowtorch, igniting the hydrogen and the oxygen in the quartz cavity, generating oxyhydrogen flame with the temperature of 900 plus 1000 ℃, and preheating the reaction cavity and the core rod;

s3 preform growth

Sending SiCl4 and GeCl4 raw material gas into oxyhydrogen flame through a blast burner to perform hydrolysis reaction, and depositing SiO2 and GeO2 powder generated by oxidation at the lower end of a core rod due to thermophoretic motion to form a core layer of a prefabricated rod; simultaneously, introducing SiCl4 raw material gas into a blast burner to enter oxyhydrogen flame, leading the gas to generate hydrolysis reaction, and depositing SiO2 powder generated by oxidation around a core layer to form an optical cladding of a prefabricated rod;

s4, growth control

S401, according to the diameter of a prefabricated rod to be produced, laser irradiates a prefabricated rod standard part with the same diameter, and laser power a is obtained through receiving of a laser receiver, the emitting power of a laser emitter adopted in the embodiment is positioned at 10mw, the power received by the laser receiver after the standard part is irradiated is 4-6mw, a is set to be 5mw, and a control parameter b is set to be 2mw and a limiting parameter c is set to be 0.2 mv;

s402, when the laser transmittance is 7mv, the lifting mechanism reduces the lifting speed of the core rod, and meanwhile, the adjusting mechanism drives the blowtorch to move in the direction of high deposition rate, namely theta is reduced, so that the theta and the lifting speed of the core rod meet the relation between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is 3mv, the lifting mechanism rapidly increases the lifting speed of the core rod, and meanwhile, the adjusting mechanism drives the blowtorch to move towards the direction with low deposition rate, namely theta is increased, so that the theta and the lifting speed of the core rod meet the relationship between the lifting speed of the core rod and the angle of the blowtorch, which is determined in the step S1 and meets the growth requirement of the formula;

when the laser transmittance is 5.2mv, the lifting mechanism carries the core rod to grow upwards at a fixed slow speed;

when the laser transmittance is 4.8mv, the lifting mechanism carries the core rod to fix and rapidly grow upwards;

s5, preform ending

After the preform is grown, the torch stops the supply of the raw material gases of SiCl4 and GeCl4, then stops the supply of hydrogen and oxygen, and opens the quartz cavity after the temperature in the quartz cavity naturally drops to room temperature and takes out the preform.

Furthermore, the core rod is always in a rotating state, the rotating speed of the core rod is 15-25r/min, and the lifting speed is 40-70 mm/h.

Furthermore, the outer wall of the quartz cavity is provided with air exhaust and air supplement, negative pressure is kept in the quartz cavity, and the negative pressure is 40-50 Pa.

Further, in step S402, the preform growth speed S is x a, where x is the optimum preform speed growth coefficient, and is selected to be 12mm/(mv · h), when the laser transmittance is 7mv, the core rod lifting speed and the burner angle are reduced so that S is 84mm/h, and the growth is accelerated, when the laser transmittance is a-b, S is 36mm/h, the preform growth speed is reduced by increasing the core rod lifting speed and the burner angle, when the laser transmittance is 5.2mv, S is a fixed speed less than 62.4mm/h, when the laser transmittance is 4.8mv, S is a fixed speed greater than 57.6mm/h, that is, the preform is controlled to be about 60mm/h, and the preform is stably grown.

Further, the device used in steps S1 to S5 includes a lower cavity 1 and an upper cavity 2, the lower cavity 1 and the upper cavity 2 are integrally formed to form a quartz cavity, an operation opening 3 is formed in the outer walls of the upper cavity 2 and the lower cavity 1, an opening/closing door 4 is installed on the operation opening 3, a three-grip chuck 5 is arranged in the upper cavity 2, a motor box 6 is fixedly installed at the top of the three-grip chuck 5, a first motor 7 is fixedly installed in the motor box 6, an output shaft of the first motor 7 is fixedly connected with the three-grip chuck 5, a lifting mechanism 8 is installed between the motor box 6 and the top plate of the upper cavity 2, a laser transmitter 10 is fixedly installed on the outer wall of one side of the lower cavity 1, a laser receiver 11 is fixedly installed on the outer wall of the lower cavity 1, a torch 14 is installed on the inner wall of the bottom of the lower cavity 1, and an adjusting mechanism 9 is installed between the torch 14 and the lower cavity 1. The plug is fixed through three chucks 5 joint, in upper cavity 2 and lower cavity 1, make the laser line between plug bottom and laser emitter 10 and laser receiver 11 align, adjust the 14 angles of blowtorch through adjustment mechanism 9, make 14 axes of blowtorch intersect with the plug axis with the plug bottom centre of a circle, then begin the prefabricated stick and grow, in the growth process, through the laser power change that laser receiver 11 received, confirm the diameter change of prefabricated stick, thereby the lifting speed of real time control plug and the angle of blowtorch 14, ensure the prefabricated stick and evenly grow.

Further, go up cavity 2 and be internal diameter 400mm, high 2000 mm's hollow circular cylinder structure, lower cavity 1 keeps away from one side of blowtorch 14 and fixedly cup joints blast pipe 12, goes up the fixed tuber pipe 13 that cup joints of outer wall of cavity 2, through blast pipe 12 and tuber pipe 13 for keep the negative pressure in cavity 2 and the lower cavity 1, be convenient for discharge remaining hydrolysate, avoid taking place the secondary growth on the prefabricated stick that has grown.

The lifting mechanism 8 comprises a mounting seat 83, the mounting seat 83 is fixed on the upper cavity 2, one end of a guide rod 81 is fixedly connected with two sides of the top of the motor box 6, once a stud 82 is fixedly connected with the middle part of the top surface of the motor box 6, the other ends of the guide rod 81 and the stud 82 penetrate through the upper cavity 2 and the mounting seat 83 in a sliding manner, a nut sleeve 86 is rotatably sleeved in the mounting seat 83, the stud 82 is sleeved in the nut sleeve 86 through a threaded structure, a toothed ring 87 is fixedly sleeved on the outer wall of the nut sleeve 86, a second motor 84 is fixedly mounted on the top of the mounting seat 83, an output shaft of the second motor 84 is fixedly connected with a gear 85, and the gear 85 is meshed with the toothed ring 87, the second motor 84 drives the gear 85 to rotate, the gear 85 drives the nut sleeve 86 to rotate through the toothed ring 87, the nut sleeve 86 drives the stud 82 to lift, thereby realizing the lifting of the core rod and realizing the change of the lifting speed by controlling the rotating speed of the second motor 84.

The adjusting mechanism 9 comprises a rotating groove 96, the rotating groove 96 is formed in one side of the lower cavity 1, the rotating groove 96 rotates to be sleeved with the rotating shaft 91, a worm gear 92 is fixedly sleeved on the rotating shaft 91, a blowtorch 14 is fixedly installed on one side, close to the inner wall of the lower cavity 1, of the worm gear 92, a fixing plate 93 is fixedly installed on the outer wall of the lower cavity 1, a third motor 95 is fixedly installed at the bottom of the fixing plate 93, an output shaft of the third motor 95 penetrates through the fixing plate 93 and is fixedly connected with a worm 94, the worm 94 is meshed with the worm gear 92, the third motor 95 drives the worm 94 to rotate, the worm 94 drives the worm gear 92 to rotate, accordingly, the pitching angle of the blowtorch 14 is changed, adjustment of the worm gear is stable, the rotating angle of the worm gear 92 is determined when the third motor 95 rotates for fixed turns, and adjustment precision is high.

Further, the torch 14 is provided with a plurality of injection lines for injecting hydrogen, oxygen, and raw material gas.

Further, this equipment is provided with the PLC controller, through PLC according to power signal automatically regulated hoist mechanism and adjustment mechanism that laser receiver 11 received.

The method comprises the steps of adjusting the growth of a prefabricated rod to be a comparison group 1 by singly controlling the lifting speed of a core rod, and controlling the growth of the prefabricated rod to be a comparison group 2 by singly controlling the angle of a blast burner, wherein the prefabricated rod grown in the embodiment of the invention, the prefabricated rod grown in the comparison group 1 and the comparison group 2 carry out diameter detection along the axial direction, the result is shown in figure 8, according to the detection result, the prefabricated rod prepared in the embodiment has large fluctuation only in the starting period, the diameter fluctuation is within 0.1mm, and the diameter fluctuation of the comparison group 1 and the comparison group 2 is large in the whole growth process, the fluctuation is about 0.5mm, so that the method can prepare the optical fiber prefabricated rod with more uniform performance by a bidirectional control method, and has high automatic control efficiency.

When in use, a core rod is fixed in the upper cavity 2 and the lower cavity 1 through the three-grab chuck 5, the second motor 84 drives the gear 85 to rotate, the gear 85 drives the nut sleeve 86 to rotate through the toothed ring 87, the nut sleeve 86 drives the stud 82 to lift, so that the lifting of the core rod is realized, the core rod is lowered, the bottom of the core rod is aligned with a laser line, the third motor 95 drives the worm 94 to rotate, the worm 94 drives the worm gear 92 to rotate, so that the pitch angle of the blowlamp 14 is changed, the axis of the blowlamp 14 is intersected with the axis of the core rod and the center of the bottom of the core rod, then hydrogen and oxygen are introduced into the blowlamp 14 and ignited in the quartz cavity to generate oxyhydrogen flame with the temperature of 900-, forming a core layer of a preform; simultaneously, SiCl4 raw material gas is introduced into a blowtorch and enters oxyhydrogen flame, so that hydrolysis reaction is carried out on the gas, SiO2 powder generated by oxidation is deposited around a core layer to form an optical cladding of a prefabricated rod, the prefabricated rod receives laser transmission power in real time through a laser receiver 11 after beginning to grow, when the laser transmission rate is 7mv, a lifting mechanism reduces the lifting speed of a core rod, and meanwhile, an adjusting mechanism drives the blowtorch to move towards the direction with high deposition rate, namely theta is reduced, and the growth of the prefabricated rod is accelerated; when the laser transmittance is 3mv, the lifting mechanism rapidly increases the lifting speed of the mandril, and simultaneously the adjusting mechanism drives the blowtorch to move towards the direction with low deposition rate, namely theta is increased, the growth of the preform is reduced, and when the laser transmittance is 5.2mv, the lifting mechanism carries the mandril to grow upwards at a fixed slow speed; when the laser transmittance is 4.8mv, the lifting mechanism carries the core rod to fix and rapidly grow upwards, so that the preform always keeps a uniform growth state.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.