WO2018098810A1 - Manufacturing device and method for optical fiber preform - Google Patents

Abstract

A manufacturing device (100) for an optical fiber preform. The manufacturing device (100) comprises a deposition target rod (14), a first blowtorch (15), and a first central control means (20). The first blowtorch (14) is connected to the first central control means (20). The manufacturing device (100) further comprises a diameter measurement unit (19) connected to the first central control means (20). The diameter measurement unit (19) is used for measuring the core diameter of a core rod (401) at preset intervals and feeds back the core diameter to the first central control means (20). The first central control means (20) presets a core diameter target, and sets a measured core diameter as a detection core diameter. When there is a deviation between the detection core diameter and the core diameter target, the first central control means (20) controls and regulates the flow rate of SiCl₄ of the first blowtorch (15).

Description

Optical fiber preform manufacturing equipment and manufacturing method thereof Technical field

The present invention relates to the field of optical fiber preform manufacturing technology, and in particular to an optical fiber preform manufacturing apparatus and a manufacturing method thereof.

Background technique

Optical fiber preform manufacturing is divided into mandrel manufacturing and outer cladding manufacturing, that is, the mandrel (including the core layer and the optical cladding) is first manufactured, and then the cladding is deposited outside the mandrel to prepare an optical fiber preform. The manufacturing methods of optical fiber preform rods mainly include axial vapor deposition (VAD), modified chemical vapor deposition (MCVD), plasma chemical vapor deposition (PCVD) and extra-tube vapor deposition (OVD), and outer cladding. The manufacturing is based on direct OVD synthesis and quartz sleeve assembly. However, no matter which method is used to manufacture the optical fiber preform, its production rate is not high due to certain factors during the manufacturing process, such as the ambient temperature at which the mandrel is exposed due to the fluctuation of the airflow during the exhaust. Fluctuations, resulting in uneven distribution of dopants in the core layer, may result in poor axial cross-section consistency.

Summary of the invention

In view of the above, it is necessary to provide an optical fiber preform manufacturing apparatus and a method of manufacturing the same that avoid the above problems.

An apparatus for manufacturing an optical fiber preform, comprising: a deposition target rod, a first burner, and a first central control device, wherein the deposition target rod is used for forming a core rod by attaching powder during deposition, the core rod comprising a core layer and An optical cladding covering the outer side of the core layer, the burner port of the deposition burner is disposed toward the deposition target rod, the first burner is connected to the first central control device, and the manufacturing apparatus further includes a caliper unit connected to the first central control device, the caliper unit is configured to measure a core diameter of the mandrel every predetermined time and feed back to the first central control device, a central control device presets a core layer diameter target, and the measured core layer diameter is a detected core layer diameter, and the first central control device controls when the detected core layer diameter deviates from the core layer diameter target The flow rate of SiCl ₄ of the first burner is adjusted.

Further, the preform has a rod position, and the first central control device sets a core diameter target corresponding to each rod position, and the core layer diameter target is a core layer diameter range, when the rod is at a rod position when the core layer of predetermined diameter smaller than the corresponding diameter in the range of the minimum threshold value or greater than the preset threshold the maximum core diameter range, the flow rate of the first torch SiCl ₄ in a first control means for controlling adjustment.

Further, the predetermined core layer has a diameter ranging from 58.3 to 58.7 mm.

Further, the manufacturing apparatus further includes a second torch, the caliper unit is further configured to detect the optical cladding diameter and feed back to the first central control device, and the first central control device is configured according to the detection The diameter of the core layer is preset to the optical cladding target of the corresponding rod position, and the diameter of the detected optical cladding is the diameter of the detection optical cladding. When the diameter of the detection optical cladding of a certain rod is smaller than the corresponding optical cladding diameter target, Then controlling to increase the flow of SiCl _{4 of} the second burner; when the diameter of the detection optical cladding of a certain rod is larger than the corresponding target of the optical cladding diameter, the flow of SiCl _{4 of the} second burner is reduced.

Further, the optical cladding target of a certain rod position is 4.15 times the diameter of the detection core layer of the corresponding rod position.

Further, the optical cladding has a diameter ranging from 240 to 244 mm.

Further, the caliper unit includes a first caliper unit for measuring a core layer diameter of the mandrel and a second caliper unit, wherein the second caliper unit is configured to measure The optical cladding diameter of the mandrel.

Further, the manufacturing apparatus further includes a temperature measuring unit connected to the first central control device, the temperature measuring unit is configured to monitor a deposition temperature of the core rod core layer and feed back the detected detection deposition temperature to The first central control device controls the H ₂ flow rate in the first burner according to the detected deposition temperature control.

A method of manufacturing an optical fiber preform, the core rod comprising a core layer and an optical cladding coated on an outer side surface of the core layer, the manufacturing method comprising monitoring a core layer diameter of the core rod, and setting the measured core layer The diameter is the diameter of the detection core layer, and when the diameter of the detection core layer deviates from the target of the predetermined core layer diameter, the flow rate of the SiCl ₄ of the first burner for providing the core growth material is adjusted.

Further, the manufacturing method further includes detecting an optical cladding diameter of the mandrel, and setting the detected optical cladding diameter to detect an optical cladding diameter, and a predetermined optical cladding target of a certain rod position is according to a corresponding rod position Detecting the core layer diameter, when the diameter of the detection optical cladding of a certain rod position is smaller than the corresponding optical cladding diameter target, then controlling the flow of SiCl ₄ of the second burner for providing the optical cladding growth material; The detecting optical cladding diameter is greater than the optical cladding diameter target of the corresponding rod position, thereby reducing the SiCl ₄ flow rate of the second burner.

Compared with the prior art, the optical fiber preform manufacturing apparatus and the manufacturing method thereof provide the adjustment of the flow rate of the SiCl ₄ according to the detection core diameter, ensure the consistency of the core layer diameter of the core rod, and improve the product of the optical fiber preform. Yield.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of an optical fiber preform manufacturing system in accordance with a preferred embodiment of the present invention.

Figure 2 is a schematic view of the end face of the preform.

Figure 3 is a schematic view of a first manufacturing apparatus.

Figure 4 is a comparison of the original process and the single bar refractive index axial test of the present embodiment.

Figure 5 is a schematic illustration of a mandrel.

Figure 6 is a schematic view of a second manufacturing apparatus.

Main component symbol description

Optical fiber preform manufacturing system	300
Preform	400
Mandrel	401
Outsourcing layer	403
Core layer	405
Optical cladding	407
Axis	409, 101
First manufacturing equipment	100
Second manufacturing equipment	200
Deposition chamber	11
Lifting device	12
Rotating device	13
Deposition target	14,207
First blowtorch	15
Second blowtorch	16
Gas supply device	17
Temperature measuring unit	18
Measuring unit	19
First central control unit	20
Ranging unit	201
Deposition blowtorch	203
Second central control device	205

The following detailed description will be made in conjunction with the accompanying drawings.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention. The features of the embodiments and examples described below can be combined with each other without conflict.

It should be noted that in the present invention, when one component is considered to be "connected" to another component, it may be directly connected to another component or may be indirectly connected to another component through the centering component.

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. The terminology used in the description of the present invention is for the purpose of describing particular embodiments and is not intended to limit the invention.

Referring to FIG. 1, the present invention provides an optical fiber preform manufacturing system 300 for fabricating a preform 400. Referring to FIG. 2, the preform 400 includes a core rod 401 and an outer cladding 403 coated on the core rod 401.

The optical fiber preform manufacturing system 300 includes a first manufacturing apparatus 100 and a second manufacturing apparatus 200. The first manufacturing apparatus 100 is for depositing and manufacturing a mandrel 401 including a starting rod made of a glass material for providing a growth base and a core layer formed by depositing a powder at an end of the starting rod 405 and an optical cladding 407 coated on the core layer 405. The core layer 405 has a higher refractive index than the optical cladding 407. The second manufacturing apparatus 200 is used to deposit the outer cladding 403. In the present embodiment, the first manufacturing apparatus 100 prepares the mandrel 401 by axial vapor deposition (VAD); the second manufacturing apparatus 200 deposits on the mandrel 401 by an out-of-pipe vapor deposition method (OVD) to form an outer cladding 403.

Referring to FIG. 3 , the first manufacturing apparatus 100 includes a deposition chamber 11 , a lifting device 12 , a rotating device 13 , a deposition target rod 14 , a first torch 15 , a second torch 16 , a gas supply device 17 , and a temperature measuring unit 18 . The caliper unit 19 and the first central control unit 20.

The lifting device 12 is disposed above the deposition chamber 11, and the rotating device 13 is mounted on the lifting device 12. The deposition target rod 14 is mounted on the rotating device 13 and housed in the deposition chamber 11. The rotating device 13 is provided with an axis 101. The lifting device 12 is used to drive the deposition target rod 14 to ascend or descend along the axis 101, and the rotating device 13 is used to drive the deposition target rod 14 to rotate about the axis 101. The deposition target rod 40 is used to adhere the powder to form the core rod 401 during deposition.

The first torch 15 and the second torch 16 are located on the lower side of the deposition chamber 11. The burner port (not shown) of the first burner 15 and the burner port (not shown) of the second burner 16 are located inside the deposition chamber 11 and are disposed toward the deposition target 14. The core layer 405 is formed by depositing powder at the end of the mandrel 401 with the first torch 15 to cause the core layer 405 to grow downward from the end of the mandrel 401. In other words, the first torch 15 is used to provide a core growth material. The second cladding lamp 16 is used to deposit a powder on the end of the mandrel 401 to form an optical cladding 407, so that the optical cladding 407 is deposited on the core layer 405 and grown downward from the end of the mandrel 401. In other words, the second torch 16 is used to provide an optical cladding growth material.

The gas supply means 17 is connected to the first burner 50 and the second burner 60 for supplying the first burner 50 and the second burner 60 with a gas such as SiCl ₄ , GeCl ₄ or the like, and a fuel such as a mixture of hydrogen and oxygen. The gas supply device 17 includes a plurality of gas supply portions (not shown). In this embodiment, the plurality of gas supply units include a SiCl ₄ supply unit, a GeCl ₄ supply unit, an Ar supply unit, an O ₂ supply unit, an H ₂ supply unit, and the like, and the plurality of gas supply units respectively pass through the pipeline and the first A burner 50 and a second burner 60 are connected. A gas control unit (not shown) is provided between each gas supply unit and the corresponding burner for controlling the gas flow at different stages. A plurality of gas control units are communicatively coupled to the first central control unit 20.

The flow rate of SiCl ₄ can be adjusted between 0.1g/min and 20g/min. At high temperature, the flame is hydrolyzed to form SiO ₂ , which is used to form the cladding and core layer of the preform; the flow rate of GeCl ₄ can be from 0.01g/min to 1.0. Adjusted between g/min, the flame is hydrolyzed to form GeO ₂ at high temperature, and is doped in the core layer to increase the refractive index of the core layer. The surface of the pipe for transporting SiCl ₄ and GeCl ₄ requires a heating belt and the temperature is controlled at 100 °C.

The H ₂ flow rate can be adjusted from 0.1 L/min to 30 L/min; the O ₂ flow rate can be adjusted from 0.1 L/min to 50 L/min, wherein H ₂ acts as a combustion, O ₂ serves as a combustion aid, and, in addition, H _{2 is} completely reacted, and it is necessary to set the O ₂ flow rate to be surplus when the flow rate is set.

Ar flow can be adjusted from 0.1 L/min to 10 L/min. There are two main functions of Ar, one of which acts as a carrier gas to carry the raw material gas; and secondly, separates H ₂ and O _{2 to} prevent mixing and reaction in the torch.

The temperature measuring unit 18 is located below the deposition chamber 11 and is spaced apart from the first burner 15 and the second burner 16. The temperature measuring unit 18 is for monitoring the deposition temperature of the core layer 405 at the end of the mandrel 401, and feeds back the detected deposition temperature to the first central control device 20 every predetermined time. The deposition temperature detected by the temperature measuring unit 18 is referred to as a detection deposition temperature. In this embodiment, the temperature measuring unit 18 is an infrared thermal imager. The first central control device 20 pre-stores a preset target temperature, a preset temperature deviation, and a preset adjustment flow rate. The first central control device 20 performs a calculation process on the detected deposition temperature and the preset target temperature, and controls the H ₂ supply unit to perform the first and second blowers 15 and 16 according to the processing result of the first central control device 20 . Perform gas supply.

The detected deposition temperature is a detection deposition temperature, and the detection deposition temperature constitutes a first group, and the first group includes t1, t2, t3, ... t(i-1), ti according to the detection sequence. The first central control device 20 takes an average of the detected deposition temperatures for N consecutive times, the average value constitutes a second group, and the second group includes t1', t2', and t3 in an average order. '...t(i-1)', ti', let t(i-1)' be the pre-value of ti', compare ti' with the preset target temperature, when ti' is compared to the pre- When the deviation of the target temperature is not greater than the preset temperature deviation, the flow rate of H ₂ in the first burner 15 remains unchanged.

When ti' is greater than the preset target temperature and the deviation between ti' and the preset target temperature is greater than the preset temperature deviation, comparing ti' with t(i-1)', if ti' If it is greater than t(i-1)', the adjustment reduces the H ₂ flow rate in the first burner 15; if ti' is less than t(i-1)', the H ₂ flow rate remains unchanged.

When ti' is smaller than the preset target temperature and the deviation between ti' and the preset target temperature is greater than the preset temperature deviation, comparing ti' with t(i-1)', if ti' When less than t(i-1)', the adjustment drop increases the H ₂ flow rate in the first burner 15.

Specifically, it is assumed that 1050 ° C is the preset target temperature, and the preset temperature deviation is set to 2 ° C, and the preset adjustment flow rate is set to 0.1 L/min. The temperature measuring unit 18 detects the deposition temperature of the core layer 405 of the mandrel 401 at a time interval of 10 seconds, which are sequentially recorded as t1, t2, t3, ... t(i-1), ti. The detecting deposition temperature constitutes a first group, which includes t1, t2, t3, ... t(i-1), ti according to the detection order. The temperature measuring unit 18 feeds back the detected deposition temperature to the first central control unit 20. The first central control unit 20 takes the detection deposition temperature five times in succession and calculates an average value. For example, the average value of t1 to t5 is recorded as t1', the average value of t2 to t6 is recorded as t2', and so on. The average constitutes a second group. The second group includes t1', t2', t3'... t(i-1)', ti'. Let t(i-1)' be the previous value of ti', for example, t2' is the previous value of t1'. Each average is compared with 1050 ° C and the previous value (such as t2 'compared with 1050 ° C and t1 '; t3 ' compared with 1050 ° C and t2 ' ...), such as an average deviation from the 1050 ° C If the average value is greater than 2 ° C, the H ₂ flow rate remains unchanged; if the average value is greater than 2 ° C above the 1050 ° C, compared with the previous value, taking t2 ' as an example, if t2 ' is greater than t1 ', the H ₂ flow rate is decreased. 0.1L/min, if t2' is less than t1', the H ₂ flow rate remains unchanged; if it is less than 2 °C than the preset target temperature, it is compared with the previous value, taking t2' as an example, if t2' is greater than t1 'The H ₂ flow rate remains unchanged. If t2' is less than t1', the H ₂ flow rate increases by 0.1 L/min.

It can be understood that the H ₂ flow rate in the burner can be controlled according to the detection deposition temperature without taking the average value.

It can be understood that if the deviation between the average value and the preset target temperature is greater than 2 ° C, the H ₂ flow rate is increased by 0.1 L/min without being compared with the previous value.

It can be understood that N detection deposition temperatures are not limited to a continuous detection sequence, which may also be randomly selected N detection deposition temperatures.

It can be understood that the temperature measuring unit 18 is not limited to detect the deposition temperature once every 10S interval, and it can also detect the acquisition at other times.

It can be understood that the preset target temperature, the preset temperature deviation, and the preset adjustment flow rate can be set according to the actual deposition process of manufacturing the preform.

It can be understood that the central control device 20 calculates a preset adjustment flow control H _{2 to} adjust the flow rate according to the detected deposition temperature and the processing result.

It can be understood that the temperature measuring unit 18 is not limited to an infrared thermal imager, which may also be other temperature sensors.

It can be understood that the detection deposition temperature constitutes a first group, which includes t1, t2, t3, ... t(i-1), ti, and averages all detected deposition temperatures of the first group. If the deviation between the average value and the preset temperature target is not greater than the preset temperature deviation, the H ₂ flow rate of the first torch 15 remains unchanged; when the deviation between the average value and the preset temperature target deviation greater than a preset temperature, H ₂ is adjusted to increase the flow rate, wherein each large 1 ℃, the H ₂ flow rate is adjusted first torch 15 is increased 0.1L / min, for example, large 1 ℃, adjusting the first burner 15 The flow rate of H ₂ is 0.1 L/min, and when it is 2 ° C, the flow rate of H _{2 of} the first burner 15 is adjusted to be 0.2 L/min.

It will be appreciated that the gas supply means 17 may be omitted and the first manufacturing apparatus 100 is connected to an external gas supply means.

It can be understood that the lifting device 12, the rotating device 13, and the deposition chamber 11 can be omitted.

Since the temperature measuring unit 18 monitors the deposition temperature of the end core layer 405 in real time during the deposition of the core layer 405 and feeds back to the first central control device 20, the first central control device 20 controls the H _{2 in} real time according to the detected deposition temperature. The flow rate ensures the stability of the surface temperature of the mandrel 401, thereby improving the stability of the refractive index of the mandrel 405. In this embodiment, based on the surface temperature acquisition technology, the gas flow rate is adjusted in real time, and the deposition of the mandrel 401 is accurately controlled, which can effectively prevent the core rod from cracking due to a large density gradient, thereby improving product quality and yield. Referring to FIG. 4, a comparison test of the axial refractive index of a single rod of the present embodiment and the original process (which does not pass the H ₂ flow rate according to the core layer deposition temperature) is shown. In this embodiment, the maximum temperature and the lowest temperature of the mandrel 401 are kept within 10 °C.

It will be appreciated that it is not limited to monitoring the deposition temperature of the end core layer 405, which may also monitor the deposition temperature of the mandrel core layer, such as an out-of-pipe vapor deposition (OVD), when the mandrel is fabricated using other processes.

The caliper unit 19 includes a first caliper unit 191 and a second caliper unit 193. The first caliper unit 191 is located below the side of the deposition chamber 11, adjacent to the temperature measuring unit 18 and disposed away from the first burner 15 for measuring the diameter of the end core 405 of the mandrel 401. The second caliper unit 193 is located below the side of the deposition chamber 11 and is disposed adjacent to the second torch 16 for measuring the diameter of the optical cladding 407 at the end of the mandrel 401. In this embodiment, the first caliper unit 191 and the second caliper unit 193 are CCD cameras. The diameter of the core layer detected by the first caliper unit 191 is the diameter of the detection core layer, and the diameter of the optical cladding layer detected by the second caliper unit 193 is the diameter of the detection optical cladding. The first caliper unit 191 detects the end core diameter every interval of the first predetermined caliper time and feeds back the detected core layer diameter to the first central control device 20, and the second caliper unit 193 is spaced apart by the second The optical cladding is detected by a preset caliper time and the detected optical cladding diameter is fed back to the first central control device 20.

Referring to FIG. 5, the diameter of the core layer is d, and the diameter of the optical cladding is D. The caliper unit 191 detects the diameter of the end core layer every 1 minute. The first central control device 20 pre-stores the core layer diameter target. In the embodiment, the predetermined core layer diameter target is a predetermined core layer diameter range, and the predetermined core layer diameter ranges from 58.3 to 58.7 mm. If the diameter of the detection core layer is within the range of 58.3 to 58.7 mm, the flow rate of SiCl _{4 of} the first burner 15 is constant; if the diameter of the detection core layer is smaller than the minimum threshold of the predetermined core diameter range, 58.3 Mm, the first central control device 20 controls the flow rate of the SiCl _{4 of the} first burner 15 to be increased by 0.05 g/min, and if the diameter of the detection core layer is greater than the maximum threshold of the predetermined core diameter range of 58.7 mm, the first A central control unit 20 controls the flow rate of the SiCl _{4 of the} first burner 15 to be lowered by 0.05 g/min.

In this embodiment, the end point of the preform 400 adjacent to the lifting device 12 is an origin, and a position along the axial direction of the preform 400 (consistent with the length direction) is a rod position, and each rod has Corresponding length (distance between the position and the origin), core diameter d and optical cladding diameter D and rod diameter (diameter of preform 400). Specifically, the first caliper unit 191 detects that the detected core layer diameter of the rod position L is d, and records both L and d into the first central control device 20.

The first central control device 20 calculates a predetermined optical cladding diameter target corresponding to the corresponding rod position according to the rod position L and its corresponding core diameter d, and the optical cladding target is the detection core diameter of the corresponding rod position. 4.15 times d. The second caliper unit 193 detects the optical cladding diameter every 1 minute, and transmits the detection optical cladding diameter to the first central control device 20. The second torch 16 has an initial SiCl ₄ flow rate of 50 g/min, which is adjusted based on the detected optical cladding diameter. When the diameter of the detection optical cladding is smaller than the optical cladding diameter target of the corresponding rod position, the flow rate of SiCl _{4 of} the second burner 16 is increased by 0.5 g/min, when the diameter of the detection optical cladding is larger than the optical cladding of the corresponding rod With the diameter target, the flow of SiCl _{4 of} the second burner 16 is reduced by 0.5 g/min.

In the mandrel obtained by the conventional process, the diameter of the core layer ranges from 58 to 60 mm, and the diameter of the optical cladding is in the range of 240 to 258 mm. The diameter of the core layer d along the axial direction is different from that of the optical cladding diameter D, D/d The fluctuation is 0.2. In the present embodiment, the diameter of the core layer deposited is in the range of 58 to 59 mm, the diameter of the optical cladding is in the range of 240 to 244 mm, and the fluctuation in D/d is 0.05. Since the diameter of the end core layer 405 is monitored by the first caliper unit 191, and the first central control device 20 adjusts the flow rate of the SiCl _{4 of the} first torch 15 according to the diameter of the monitoring core layer, thereby ensuring the consistency of the core diameter of the deposition growth. And the first central control device 20 sets the optical cladding target according to the detection core diameter of the corresponding rod position, and adjusts the flow of the SiCl _{4 of the} second burner 16 according to the optical cladding target and the detection optical cladding diameter to perform dynamic precision The regulation ensures the consistency of the optical cladding diameter and further ensures the consistency of the core-package ratio, thereby improving the manufacturing yield of the mandrel 401.

It can be understood that the time when the first caliper unit 191 and the second caliper unit 193 detect the interval is not limited.

It can be understood that the first caliper unit 191 and the second caliper unit 193 are not limited to a CCD camera, and may also be other measurement distance sensors, such as an ultrasonic sensor.

It can be understood that the caliper unit 190 can be a caliper unit disposed under the deposition chamber 11, and then the image is processed by the image processing unit in the first central control device 20 to obtain the core diameter and the diameter of the optical cladding. .

It can be understood that the first central control device 20 pre-stores corresponding preset core layer diameter range, core layer diameter target and optical cladding diameter target according to each rod position, according to the detected core layer diameter and the preset core layer diameter range. adjusting the flow rate of SiCl ₄ of a second burner 16, based on the monitored optical cladding diameter and the clad diameter of the optical target adjusting SiCl ₄ detector 16 flow of the second torch.

The second manufacturing apparatus 200 is for depositing on the mandrel 401 by an out-of-pipe vapor deposition method (OVD) to form an outer cladding 403 to form the preform 400. The preform 400 coincides with the axis 101 along its longitudinal axis.

Referring to FIG. 6, the second manufacturing apparatus 200 is provided with a distance measuring unit 201, a deposition torch 203, a second central control unit 205, and a deposition target rod 207. The ranging unit 201 and the deposition torch 203 are communicatively coupled to the second central control unit 205. The ranging unit 201 is used to monitor the rod diameter of the preform 400. In the present embodiment, the distance measuring unit 201 is an ultrasonic range finder. It will be appreciated that the second manufacturing apparatus 200 also includes other necessary or non-essential structures, such as deposition cavities, which are not described herein.

The preform 400 has an axis 409 (along the length of the preform). The ranging unit 201 and the deposition torch 203 are movable relative to the preform 400 along an axis generally parallel to the axis 409. The second central control device 205 pre-stores the first motion path of the ranging unit 201 along an axis parallel to the axis 409, and controls the ranging unit 201 to move according to the first motion path when detecting the rod diameter, and controls the ranging Unit 201 detects the rod diameter and its corresponding rod position at regular intervals. The second central control device 205 pre-stores a second path of motion of the deposition torch 203 along an axis parallel to the axis 409 and controls the deposition torch 203 to move in accordance with the second path of motion and to record the bar relative to the preform 400 .

The distance measuring unit 201 and the deposition torch 203 are movable relative to the preform 400. When the distance measuring unit 201 moves to the corresponding rod position, the rod diameter of the preform 400 is detected and the detection rod diameter is fed back to the The second central control device 205, the central control device 205 presets a reference rod diameter, and the second central control device 205 compares the detection rod diameter corresponding to each rod position with the reference rod diameter. The flow of SiCl ₄ when the deposition torch 203 is moved to the corresponding rod position is adjusted.

When the detection rod diameter of a certain rod position is larger than the reference rod diameter, the second central control device 205 controls the movement of the deposition torch 203 to the corresponding rod position to reduce the flow of the SiCl _{4 of} the deposition burner 203; When the detection rod diameter of a certain rod position is smaller than the reference rod diameter, the second central control device 205 controls to increase the flow rate of the SiCl _{4 of} the deposition burner when the deposition torch 203 is moved to the corresponding rod position.

In this embodiment, the ranging unit 201 tests the real-time bar diameter distribution every 5 minutes. During the test, the ranging unit 201 detects the rod diameter of the preform 400 along the axis parallel to the axis 409 of the preform 400 relative to the preform 400 and feeds back the detection rod diameter and the corresponding position (recording a rod diameter every 2 mm) to The second central control device 205, for example, the first rod diameter B1 and its corresponding rod position L1, the second rod diameter B2 and its corresponding rod position L2, the third rod diameter, and so on. The second central control device 205 calculates the average value B' of the detection rod diameters (B1, B2, ...) as a reference rod diameter, and calculates a relationship between the detection rod diameter of each point and the reference rod diameter B'. The rod diameter difference, for example, the rod diameter difference between B1 and B' is B1', the rod diameter difference between B2 and B' is B2'..., and so on. The second central control device 205 associates the rod diameter difference with the movement path of the deposition torch 205, and at the corresponding rod position, when the deviation between the reference rod diameter and the detection rod diameter is different by 1 mm, the deposition torch 205 travels to correspond At the rod position, the flow rate of SiCl _{4 of the} deposition torch 205 was adjusted accordingly to 0.5 g/min.

It can be understood that the ranging unit 201 and the deposition torch 203 do not define movement relative to the preform 400 along an axis parallel to the axis 409 of the preform 400, and the ranging unit 201 can measure the diameter of the preform 400. Alternatively, the deposition torch 203 can provide the preform 400 with a material for deposition growth.

It can be understood that the ranging unit 201 is configured to monitor the rod diameter of the preform 400 and feed back the detected detection rod diameter to the second central control device 205, and the second central control device 205 is configured according to the The rod diameter is adjusted to adjust the flow of SiCl ₄ of the deposition torch.

It can be understood that the reference rod diameter may not be the average value of the detection rod diameter, and the second central control device 205 corresponds to the required preset reference rod diameter, and the second central control device 205 corresponds to each rod position. The comparison between the detection rod diameter and the reference rod diameter adjusts the flow rate of the SiCl ₄ of the deposition torch at the corresponding rod position.

Conventionally, a preform formed by forming an outer layer is deposited on the mandrel by an out-of-pipe vapor deposition method (OVD), the rod diameter ranges from 239 to 246 mm, and the rod diameter fluctuates to 8 mm. In the embodiment, the second central control device 205 controls the deposition torch 205 to adjust the flow of the SiCl ₄ at the corresponding rod position according to the detection rod diameter detected by the ranging unit 201, thereby realizing the correction of the rod diameter during the deposition process, and the rod is corrected. The diameter ranges from 241 to 243 mm, and the diameter of the single rod fluctuates by 2 mm. The rod diameter of the preform 400 has a good consistency, and the performance and manufacturing yield of the preform 400 are further improved. In addition, the mode field diameter and the cut-off wavelength of the preform 400 in the axial direction can be increased. In the present embodiment, the standard deviation of the preform 400 after drawing is 11 and the over-standard ratio is 0.1%.

The invention also provides a method for manufacturing an optical fiber preform, which comprises the following steps:

In step 601, a powder is attached to the deposition target rod to form a core rod, and the core rod includes a core layer and an optical cladding. In this embodiment, the mandrel is fabricated by an axial vapor deposition method. The deposition target rod can be used to provide a first torch movement that provides a core growth material.

In step 602, the powder is deposited on the optical cladding of the mandrel to form an outer layer, thereby forming a preform. In this embodiment, the mandrel is fabricated by an out-of-pipe vapor deposition method.

In step 601, the method further includes monitoring a deposition temperature of the core layer 405 of the mandrel, and controlling the H ₂ flow rate in the first torch providing the core growth material according to the deposition temperature of the monitoring core layer.

Further, the deposition temperature of the core layer is detected every predetermined time interval, and the detected deposition temperature is a detection deposition temperature, and the detection deposition temperature is a first group, and the first group includes the detection sequence. T1, t2, t3, ... t(i-1), ti, taking the average of the detected deposition temperatures for N consecutive times, the average value constitutes the second group, and the second group is in the average order Including t1', t2', t3'...t(i-1)', ti', let t(i-1)' be the pre-value of ti', compare ti' with the preset target temperature, when When the deviation of ti' from the preset target temperature is not greater than the preset temperature deviation, the H ₂ flow rate in the first torch remains unchanged, when ti' is between the preset target temperature When the deviation is greater than the preset temperature deviation, comparing ti' with t(i-1)', and adjusting the first burner according to the difference between the ti' and t(i-1)' H ₂ traffic.

When ti' is greater than the preset target temperature and the deviation between ti' and the preset target temperature is greater than the preset temperature deviation, comparing ti' with t(i-1)', if ti' If it is greater than t(i-1)', the adjustment reduces the H ₂ flow rate in the first burner 15; if ti' is less than t(i-1)', the H ₂ flow rate remains unchanged.

When ti' is smaller than the preset target temperature and the deviation between ti' and the preset target temperature is greater than the preset temperature deviation, comparing ti' with t(i-1)', if ti' When less than t(i-1)', the adjustment decreases the H ₂ flow rate in the first burner.

Specifically, it is assumed that 1050 ° C is the preset target temperature, and the preset temperature deviation is set to 2 ° C, and the preset adjustment flow rate is set to 0.1 L/min. The deposition temperature of the core layer 405 at the end of the mandrel 401 is detected once every 10 seconds, and is sequentially recorded as t1, t2, t3, t4, t5, t6, t7, t8, t9, . The detecting deposition temperature constitutes a first group comprising t1, t2, t3, t4, t5, t6, t7, t8, t9, . The temperature measuring unit 18 feeds back the detected deposition temperature to the first central control unit 20. The first central control unit 20 takes the detection deposition temperature five times in succession and calculates an average value. For example, the average value of t1 to t5 is recorded as t1', the average value of t2 to t6 is recorded as t2', and so on. The average constitutes a second group. The second group includes t1', t2', t3'. T2' is the previous value of t1'. Each average is compared with 1050 ° C and the previous value (such as t2 'compared with 1050 ° C and t1 '; t3 ' compared with 1050 ° C and t2 ' ...), such as an average deviation from the 1050 ° C If the value is not more than 2 ° C, the H ₂ flow rate remains unchanged; if the average value is greater than 2 ° C above the 1050 ° C, compared with the previous value, taking t2 ' as an example, if t2 ' is greater than t1 ' then the first burner The H ₂ flow rate is reduced by 0.1 L/min. If t2' is less than t1', the H ₂ flow rate remains unchanged; if it is 2 ° C or more smaller than the preset target temperature, it is compared with the previous value, taking t2' as an example, such as t2'. If it is greater than t1', the H ₂ flow rate remains unchanged. If t2' is less than t1', the H ₂ flow rate is increased by 0.1 L/min.

It can be understood that if the deviation between the average value and the preset target temperature is greater than 2 ° C, the H ₂ flow rate of the first burner is increased by 0.1 L/min without being compared with the previous value.

It can be understood that N detection deposition temperatures are not limited to a continuous detection sequence, which can also be randomly extracted N detection deposition temperatures.

It can be understood that the preset target temperature is set to a preset temperature deviation of 2 ° C, and the preset adjustment flow rate can be set in the process of actually depositing the preform.

It can be understood that the method is not limited to the use of the axial vapor deposition method, and may be other methods such as an out-of-pipe vapor deposition method, an improved chemical vapor deposition method (MCVD), or a plasma chemical vapor deposition method (PCVD), as long as it can be in the core. During the deposition process of the layer, the flow rate of H ₂ is adjusted in real time by monitoring the deposition temperature of the core layer and ensuring the stability of the temperature according to the deposition temperature of the core layer.

In step 601, further comprising monitoring a core layer diameter, wherein the measured core layer diameter is a detected core layer diameter, and adjusting the core for providing the core when the detected core layer diameter deviates from a predetermined core layer diameter target The flow rate of SiCl ₄ of the first burner of the layer growth material. In this embodiment, the diameter of the core layer is the diameter of the end of the core layer, and the predetermined core layer diameter is the predetermined core layer diameter range.

The SiCl ₄ flow rate of the first burner for providing the core growth material is adjusted when it is detected that the end core diameter is not within the preset core diameter range.

Further, when detecting that the core layer diameter is smaller than a minimum threshold value of the preset core layer diameter range, adjusting the flow rate of the SiCl _{4 of the} first torch is adjusted; when detecting that the end cladding diameter is larger than the maximum threshold of the preset core diameter range At the time, the flow rate of the SiCl ₄ of the first burner is adjusted.

The diameter of the core layer is d, and the diameter of the optical cladding is D. The caliper unit 191 detects the diameter of the end core layer every 1 minute. In this embodiment, the predetermined core layer diameter ranges from 58.3 to 58.7 mm. If the diameter of the detection core layer is within the range of 58.3 to 58.7 mm, the flow rate of SiCl _{4 of} the first burner 15 is constant; if the diameter of the detection core layer is smaller than the minimum threshold of the predetermined core diameter range, 58.3 Mm, the flow rate of the SiCl _{4 of the} first burner 15 is controlled to increase by 0.05 g/min, and if the diameter of the core layer is greater than the maximum threshold of the predetermined core diameter of 58.7 mm, the first burner 15 is controlled to be adjusted. The SiCl ₄ flow rate was reduced by 0.05 g/min.

In step 601, the method further comprises: detecting an optical cladding diameter of the mandrel, setting the detected optical cladding diameter to detect an optical cladding diameter, and detecting a predetermined optical cladding target of a certain rod position according to the detection of the corresponding rod position The core layer diameter is set, when the diameter of the detection optical cladding of a certain rod position is smaller than the corresponding optical cladding diameter target, then controlling the flow of SiCl ₄ of the second burner for providing the optical cladding growth material; Detecting the optical cladding diameter larger than the optical cladding diameter target of the corresponding rod position reduces the SiCl ₄ flow rate of the second burner.

In this embodiment, the optical cladding target is preset according to the rod position, and the predetermined optical cladding target is 4.15 times the diameter d of the detection core of the corresponding rod position.

Further, when the detecting optical cladding diameter is smaller than the optical cladding diameter target of the corresponding rod position, adjusting the flow rate of the second burner for providing the optical cladding growth material; when the detection optical cladding diameter is larger than The optical cladding diameter target of the corresponding rod position is adjusted to reduce the flow rate of the second burner for providing the optical cladding growth material.

Specifically, according to the rod position L and its corresponding core layer diameter d, the calculation process results in a predetermined optical cladding diameter target, which is 4.15 times the diameter d of the detection core layer of the corresponding rod position. The end optical cladding diameter was measured every 1 minute. The second torch 16 has an initial SiCl ₄ flow rate of 50 g/min, which is adjusted based on the detected optical cladding diameter. When the diameter of the detection optical cladding is smaller than the optical cladding diameter target of the corresponding rod position, the flow rate of the second burner 16 is increased by 0.5 g/min, when the diameter of the detection optical cladding is larger than the optical cladding diameter target of the corresponding rod Then, the flow rate of the second burner 16 is reduced by 0.5 g/min.

It can be understood that the method is not limited to the use of the axial vapor deposition method, and may be other methods such as an out-of-pipe vapor deposition method, an improved chemical vapor deposition method (MCVD), or a plasma chemical vapor deposition method (PCVD), as long as it can be in the core. During the deposition and growth of the layer and the optical cladding, the flow rate of the SiCl _{4 of the} first and second burners is adjusted in real time by monitoring the diameter of the core layer and the diameter of the optical cladding, thereby ensuring the uniformity of the diameter of the core layer and the uniform diameter of the optical cladding. Sex.

In step 602, the method further includes monitoring the rod diameter of the preform, and adjusting the flow rate of the SiCl ₄ of the deposition burner according to the detected detection rod diameter.

Monitoring the rod diameter of the preform by a distance measuring unit, the distance measuring unit and the deposition burner are movable relative to the preform, the preform has a rod position, and the distance measuring unit detects when moving to a corresponding rod position The rod diameter of the preform is adjusted according to the result of comparing the detection rod diameter of each rod position with the reference rod diameter, and the flow of SiCl ₄ when the deposition torch moves to the corresponding rod position. In the present embodiment, the distance measuring unit is an ultrasonic range finder. The ranging unit detects the rod diameter and its corresponding rod position at regular intervals.

In this embodiment, the ranging unit tests the real-time bar diameter distribution every 5 minutes. In the test, the distance measuring unit detects the rod diameter relative to the preform movement along an axis parallel to the axis of the preform and records the detection rod diameter and the corresponding position, for example, the first rod diameter B1 and its corresponding rod position L1, and second The rod diameter B2 and its corresponding rod position L2, the third rod diameter..., and so on. Calculating the average value B' of the detection rod diameters (B1, B2, ...) as a reference rod diameter, and calculating the rod diameter difference between the actual rod diameter of each point and the reference rod diameter B', for example The difference between the rod diameters between B1 and B' is B1', the difference between the rod diameters between B2 and B' is B2'..., and so on. The rod diameter difference is associated with the deposition torch movement path, and the diameter difference is 1 mm. When the deposition torch travels to the corresponding rod position, the SiCl ₄ flow rate is adjusted by 0.5 g/min.

It can be understood that the manufacturing method includes monitoring the rod diameter of the preform through a distance measuring unit, and adjusting the flow rate of the SiCl ₄ of the deposition burner according to the detected detection rod diameter.

It can be understood that the ranging unit can move relative to the preform, the preform has a rod position, and when the ranging unit moves to a corresponding rod position, the rod diameter of the preform is detected, corresponding to each rod position. As a result of comparing the test rod diameter with the reference rod diameter, the flow of SiCl ₄ when the deposition burner is moved to the corresponding rod position is adjusted.

The optical fiber preform manufacturing device and the manufacturing method thereof provide real-time control of adjusting the flow rate of H ₂ according to the detection deposition temperature, thereby ensuring the stability of the surface temperature of the mandrel, thereby improving the stability of the refractive index of the mandrel and improving the stability of the core rod. Product yield of optical fiber preforms. Further, adjusting the flow rate of the SiCl _{4 of the} first burner according to the condition of monitoring the diameter of the core layer, thereby ensuring the consistency of the core diameter of the deposition growth, and setting the optical cladding target according to the diameter of the detection core layer of the corresponding rod position, and according to the The optical cladding target and the detection optical cladding diameter adjust the flow rate of the second burner to perform dynamic precise adjustment, ensure the consistency of the optical cladding diameter, and further ensure the consistency of the core-package ratio, and improve the manufacturing yield of the core rod . Moreover, according to the detection rod diameter detected by the ranging unit, the deposition torch is adjusted to adjust the flow of SiCl ₄ at the corresponding rod position, thereby realizing the correction of the rod diameter during the deposition process, so that the rod diameter of the preform is very consistent. To further improve the performance and manufacturing yield of the preform.

It is to be understood that those skilled in the art can make other variations and the like in the spirit of the present invention for use in the design of the present invention as long as it does not deviate from the technical effects of the present invention. All changes made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims (10)

1. An apparatus for manufacturing an optical fiber preform, comprising: a deposition target rod, a first burner, and a first central control device, wherein the deposition target rod is used for forming a core rod by attaching powder during deposition, the core rod comprising a core layer and An optical cladding covering the outer side of the core layer, the burner port of the deposition burner is disposed toward the deposition target rod, and the first burner is connected to the first central control device, wherein: The manufacturing apparatus further includes a caliper unit connected to the first central control device, the caliper unit is configured to measure a core diameter of the mandrel every predetermined time and feed back to the first central control device The first central control device presets a core layer diameter target, and the measured core layer diameter is a detected core layer diameter, and when the detected core layer diameter deviates from the core layer diameter target, the first The central control device controls the flow rate of the SiCl ₄ of the first burner.
2. The apparatus for manufacturing an optical fiber preform according to claim 1, wherein said preform has a rod position, and said first central control device sets a core diameter target corresponding to each rod position, said core layer diameter target a range of diameters of the core layer, when the diameter of the detection core layer at a rod position is less than a minimum threshold value of a range of the corresponding predetermined core layer diameter or a maximum threshold value greater than a range of the predetermined core layer diameter, the first medium control means for controlling said adjusting the flow rate of SiCl ₄ first torch.
3.  The apparatus for manufacturing an optical fiber preform according to claim 2, wherein said predetermined core layer has a diameter ranging from 58.3 to 58.7 mm.
4. The apparatus for manufacturing an optical fiber preform according to claim 2, wherein said manufacturing apparatus further comprises a second torch, said caliper unit further configured to detect said optical cladding diameter and feed back to said first a central control device, the first central control device presets an optical cladding target of the corresponding rod position according to the diameter of the detection core layer, and sets the detected optical cladding diameter to detect the optical cladding diameter, when a certain rod position When detecting that the optical cladding diameter is smaller than the corresponding optical cladding diameter target, then controlling increases the flow of SiCl _{4 of} the second burner; when the diameter of the detection optical cladding of a certain rod is larger than the corresponding optical cladding diameter target, then decreasing The flow of SiCl _{4 of the} second burner.
5.  The optical fiber preform manufacturing apparatus according to claim 4, wherein the optical cladding target of a certain rod position is 4.15 times the diameter of the detection core layer of the corresponding rod position.
6.  The optical fiber preform manufacturing apparatus according to claim 4, wherein said optical cladding has a diameter ranging from 240 to 244 mm.
7.  The apparatus for manufacturing an optical fiber preform according to claim 4, wherein the caliper unit comprises a first caliper unit and a second caliper unit, and the first caliper unit is configured to measure the mandrel The diameter of the core layer, the second caliper unit is used to measure the optical cladding diameter of the mandrel.
8. The apparatus for manufacturing an optical fiber preform according to any one of claims 1 to 7, wherein the manufacturing apparatus further comprises a temperature measuring unit connected to the first central control unit, wherein the temperature measuring unit is used for monitoring the Determining a deposition temperature of the core layer of the core rod and feeding back the detected detection deposition temperature to the first central control device, the first central control device controlling the H _{2 in} the first burner according to the detection deposition temperature control flow.
9. A method of manufacturing an optical fiber preform, the core rod comprising a core layer and an optical cladding layer coated on an outer side surface of the core layer, wherein the manufacturing method comprises monitoring a core layer diameter of the core rod, and measuring The diameter of the core layer obtained is the diameter of the detection core layer, and when the diameter of the detection core layer deviates from the target diameter of the predetermined core layer, the flow rate of the SiCl ₄ of the first burner for providing the core growth material is adjusted.
10. The method of manufacturing an optical fiber preform according to claim 9, wherein the manufacturing method further comprises detecting an optical cladding diameter of the core rod, and setting the detected optical cladding diameter to detect an optical cladding diameter. The preset optical cladding target of a certain rod position is set according to the detection core diameter of the corresponding rod position, and when the detection optical cladding diameter of a certain rod position is smaller than the corresponding optical cladding diameter target, the control is increased for providing The SiCl ₄ flow rate of the second burner of the optical cladding growth material; when the diameter of the detection optical cladding is greater than the optical cladding diameter target of the corresponding rod position, the SiCl ₄ flow rate of the second burner is reduced.

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