Description:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“SYSTEM AND METHOD TO DRAW OPTICAL FIBER”

APPLICANTS:

Name : Sterlite Technologies Limited

Nationality : Indian

Address : 15th & 16th Floor, Capital Cyberscape, Sector –
59, Gurugram, Haryana-122102, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION
The present invention relates to optical fibers, and more particularly to system and method to draw an optical fiber.
BACKGROUND
Optical fibers are widely used in optical cables. Optical fibers are usually drawn from a glass preform, which is a cylindrical body made up of glass. The optical fiber is then passed through one or more cooling stage for cooling the drawn optical fiber prior to applying coating on the drawn optical fiber. In general, the drawn optical fiber is passed through a cooling tube in presence of one or more gas or fluid to perform cooling of the drawn optical fiber. The studies have shown that lower part (usually 1/3rd of the length) of the cooling tube does not contribute much to cooling of the optical fiber as compared to the upper part (top 2/3rd of the length) of the cooling tube.
While there are various mechanisms to draw an optical fiber from a glass preform. Also, there are various references for cooling apparatus to cool bare optical fiber during optical fiber draw process. The existing cooling apparatus lacks in efficient sealing of the cooling apparatus and effective positioning of recovery port in the cooling apparatus. This causes wastage of the inert gas that is supplied inside the cooling apparatus. For example, a Chinese reference CN113772948A discloses an apparatus for cooling optical fiber in presence of helium gas. Another Chinese reference CN85101537A discloses a cooling apparatus that cools optical fiber in presence of helium and hydrogen. The cooling apparatus is sealed by a pipe at the bottom. However, conventional cooling apparatuses lack to manage unnecessary losses of inert gas. Hence a lot of inert gas is wasted which could be easily recovered and reused.
In light of the above stated discussion, there is a need for an efficient and effective system and method to draw an optical fiber that overcomes the above stated disadvantages.
Therefore, there is a need for an optical fiber cable that overcomes one or more limitation associated with the available optical fiber cables.
OBJECT OF INVENTION
The principal object of the embodiments herein is to provide system and method to draw an optical fiber.
SUMMARY
In an aspect of the present disclosure, a method for drawing an optical fiber is disclosed. The method has a step of melting a cylindrical glass preform in a draw furnace to obtain a bare optical fiber. The method further has a step of cooling the bare optical fiber inside the cooling tube. The cooling tube has at least one inlet port and at least one recovery port. The method further has a step of supplying at least one inert gas inside the cooling tube from the at least one inlet port. The method further has a step of recovering the at least one inert gas from the at least one recovery port. The at least one recovery port may be positioned at an intermediate position along a longitudinal axis of the cooling tube. The intermediate position may be below a middle point and above a bottom end of the cooling tube. The method further has a step of coating the cooled bare optical fiber to obtain the optical fiber.
These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
FIG. 1 illustrates a schematic view of an optical fiber drawing system, accordingly to the embodiments disclosed herein;
FIG. 2 illustrates a side view of a cooling tube of the optical fiber drawing system, accordingly to the embodiments disclosed herein;
FIG. 3 illustrates a side view of a cooling tube with a choking device of the optical fiber drawing system, accordingly to the embodiments disclosed herein;
FIG. 4 illustrates a block diagram of an intercooler device for recovering a gas, accordingly to the embodiments disclosed herein;
FIG. 5 illustrates a block diagram representing recovery and recirculation unit of the optical fiber drawing system of FIG. 1, accordingly to the embodiments disclosed herein; and
FIG. 6 illustrates a flowchart of a method for drawing the optical fiber, accordingly to the embodiments disclosed herein.
It should be noted that the accompanying figures are intended to present illustrations of exemplary aspects of the present disclosure. These figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.
DETAILED DESCRIPTION OF FIGURES
The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
As used herein the term “optical fiber” is referred to as a light guiding medium that provides high-speed data transmission. The optical fiber comprises one or more glass cores and one or more glass cladding layers. The light moving through the one or more glass cores of the optical fiber relies upon the principle of total internal reflection, where the one or more glass core has a higher refractive index than the refractive index of the cladding of the optical fiber. Further, the glass cladding of the optical fiber is coated with one or more coating layers to protect the glass part of the optical fiber.
The term “core” of an optical fiber as used herein is referred to as the one or more cylindrical structure present in the center or in a predefined lattice of the optical fiber that is configured to guide the light rays inside the optical fiber. In other words, the core may be defined as the inner most cylindrical structure that is present in the optical fiber and is configured to guide the light rays inside the optical fiber.
The term “cladding” of an optical fiber as used herein is referred to as one or more layered structure covering the core of an optical fiber from the outside that is configured to possess a lower refractive index than the refractive index of the core to facilitate total internal reflection of light rays inside the optical fiber. In other words, the cladding is defined as one or more layered structure covering the core of the optical fiber from the outside. The cladding is configured to possess a lower refractive index than the refractive index of the core to facilitate total internal reflection of light rays inside the optical fiber. Further, the cladding of the optical fiber may include an inner cladding layer coupled to the outer surface of the core of the optical fiber and an outer cladding layer coupled to the inner cladding from the outside.
The term “glass preform” as used herein refers to a solid cylindrical body made up of glass that is melted and drawn to form an optical fiber. The cylindrical glass preform is designed to have the desired refractive index profile for the optical fiber.
The term “draw furnace” as used herein is referred to as a high-temperature chamber used for melting the glass preform and drawing the optical fiber. To start the drawing, the glass preform is lowered into the furnace chamber. Generally, the drawing region is heated above 1,800° C, where the glass softens and elongates with a teardrop-shaped drip pulling the optical fiber downward.
The term “refractive index” as used herein refers to measure of change of speed of light from one medium to another medium for example vacuum. In other words, the refractive index may be particularly measured in reference to the speed of light in vacuum. The refractive index facilitates measurement of bending of light from one medium to another medium.
The term “refractive index profile” is also termed as a relative refractive index profile (?(r)) of the optical fiber. The refractive index profile is referred to as the distribution of refractive indices in the optical fiber from the core to the outmost cladding layer of the optical fiber. Based on the refractive index profile, the optical fiber may be configured as a step index fiber. The refractive index of the core of the optical fiber is constant throughout the optical fiber and is higher than the refractive index of the cladding. Further, the optical fiber may be configured as a graded index fiber such that the refractive index of the core gradually varies as a function of the radial distance from the center of the core. The optical fiber may be of any type of optical fiber without deviating from the scope of the present disclosure.
The term “attenuation” is used to describe reduction in power of a light signal as it is transmitted. Specifically, the attenuation is caused by Rayleigh scattering, and absorption of the light signal.
The term “residence time” is time period between injection of an inert gas (helium) till a suction device initiates suction of mixture of the inert gas and air from the cooling tube. In an example, volume of the inert gas may be 10 m3 that may be injected into the cooling tube. In another example, the volume of the inert gas may be any value without deviating from the scope of the present disclosure.
The detailed description of the appended drawings is intended as a description of the currently preferred aspects of the present disclosure, and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different aspects that are intended to be encompassed within the spirit and scope of the present disclosure.
Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present technology. Similarly, although many of the features of the present technology are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present technology is set forth without any loss of generality to, and without imposing limitations upon, the present technology.
FIG. 1 illustrates a schematic view of an optical fiber drawing system 100 (hereinafter referred to and designated as “the system 100”). The system 100 may facilitate drawing an optical fiber from a glass preform. The system 100 may enhance production rates of the optical fiber. Specifically, the system 100 may enhance production rates without increasing consumption of an inert gas (helium) in cooling tubes.
The system 100 may have a draw furnace 102, an annealing furnace 104, a cooling tube 106, a coating apparatus 108, a curing device 110, a capstan 112, an idler pulley 114, and a take up spool 116.
The draw furnace 102 may be disposed at an upper side of the system 100. The draw furnace 102 may be adapted to receive a cylindrical glass preform 118 (hereinafter referred to and designated as “the glass preform 118”). The draw furnace 102 may have a hollow chamber (not shown) that may be adapted to accept the glass preform 118. Specifically, the glass preform 118 may be inserted through a first cylindrical portion (not shown) of the hollow chamber such that the glass preform 118 ejects from a second cylindrical portion (not shown) of the hollow chamber. The draw furnace 102 may further be adapted to raise temperature of the glass preform 118 that facilitates melting of the glass preform 118. The glass preform 118, upon melting, may facilitate generation of a bare optical fiber 120. The bare optical fiber 120 may be drawn from the draw furnace 102.
The annealing furnace 104 may be coupled to the draw furnace 102. Specifically, the annealing furnace 104 may be disposed downstream of the draw furnace 102. In other words, the bare optical fiber 120 may be transferred from the draw furnace 102 to the annealing furnace 104. The annealing furnace 104 may be adapted to receive the bare optical fiber 120. Specifically, the bare optical fiber 120 may be received from an upper end of the annealing furnace 104. The annealing furnace 104 may further be adapted to gradually lower the temperature of the bare optical fiber 120. In other words, the annealing furnace 104 may be adapted to gradually cool the bare optical fiber 120 in one or more annealing stages. Specifically, the annealing furnace 104 may be adapted to lower an attenuation of the bare optical fiber 120 by lowering an effective temperature of the bare optical fiber 120.
In some aspects of the present disclosure, the attenuation of the bare optical fiber 120 may be less than 0.32 Decibels (dB) at a wavelength of 1310 nanometers (nm). In some aspects of the present disclosure, the bare optical fiber 120 may have a diameter that may be in a range of 60 micrometer (µm) to 125 µm with tolerance of 1 µm. In some aspects of the present disclosure, the bare optical fiber may have the diameter of any value without deviating from the scope of the present disclosure.
The cooling tube 106 may be coupled to the annealing furnace 104. Specifically, the cooling tube 106 may be disposed downstream of the annealing furnace 104. In other words, the bare optical fiber 120 may be transferred from the annealing furnace 104 to the cooling tube 106. The cooling tube 106 may be adapted to receive the bare optical fiber 120 that may be annealed by the annealing furnace 104. The cooling tube 106 may be adapted to lower the temperature of the bare optical fiber 120. In other words, the cooling tube 106 may be adapted to cool down the bare optical fiber 120 after annealing the bare optical fiber 120. The cooling tube 106 may be adapted to cool down the bare optical fiber 120 by passing at least one cooling fluid or at least one inert gas through the cooling tube 106. Specifically, to cool down the bare optical fiber 120, the cooling tube 106 may facilitate contact of the at least one cooling fluid or the at least one inert gas with the bare optical fiber 120. In other words, when the at least one cooling fluid or the at least one inert gas may come in contact with the bare optical fiber 120, the temperature of the bare optical fiber 120 is reduced. Thus, the at least one cooling fluid or the at least one inert gas may facilitate cooling of the bare optical fiber 120. The flow of the at least one cooling fluid or the at least one inert gas needs to be monitored or controlled inside the cooling tube 106 to avoid degradation of optical parameters of the bare optical fiber 120. The amount and residence time of the at least one cooling fluid or the at least one inert gas injected inside the cooling tube 106 may be managed efficiently to control vibration and turbulence inside the cooling tube 106. If the vibration or turbulence inside the cooling tube 106 increases beyond a certain range, this may lead to breaking of the bare optical fiber 120. The controlled vibration and turbulence inside the cooling tube 106 is good for heat extraction from the bare optical fiber 120.
The coating apparatus 108 may be coupled to the cooling tube 106. Specifically, the coating apparatus 108 may be disposed downstream of the cooling tube 106. In other words, the bare optical fiber 120 may be transferred from the cooling tube 106 to the coating apparatus 108. The coating apparatus 108 may have one or more coating devices (not shown) that are adapted to coat the bare optical fiber 120. In other words, the one or more coating devices may be adapted to apply a coating layer on the bare optical fiber 120. Specifically, the one or more coating devices may be adapted to coat the bare optical fiber 120 with one or more primary coating materials and one or more secondary coating materials to generate a coated optical fiber 122. The one or more primary coating materials and the one or more secondary coating materials may be adapted to protect the surface of the bare optical fiber 120. Thus, the one or more primary coating materials and the one or more secondary coating materials may advantageously facilitate to improve strength of the bare optical fiber 120. The one or more primary coating materials and the one or more secondary coating materials may be excellent in terms of heat resistance, cold resistance, and may demonstrate stable function over a wide temperature range. Thus, the one or more primary coating materials and the one or more secondary coating materials may protect the coated optical fiber 122 from cracks and thus makes the coated optical fiber 122 resistant to abrasion and scratches.
In some aspects of the present disclosure, each of the one or more secondary coating materials may be a coloured secondary coating material.
In some aspects of the present disclosure, the one or more primary coating materials and the one or more secondary coating materials may facilitate colour coding of the coated optical fiber 122.
The curing device 110 may be coupled to the coating apparatus 108. Specifically, the curing device 110 may be disposed downstream of the coating apparatus 108. In other words, the coated optical fiber 122 may be transferred from the coating apparatus 108 to the curing device 110. The curing device 110 may be adapted to cure the coated optical fiber 122. Specifically, the curing device 110 may be adapted to cure the coated optical fiber 122 by way of an ultraviolet (UV) radiation. The curing device 110 may have an ultraviolet source, for example, an ultraviolet lamp or an ultraviolet light and/or an LED that may be adapted to produce the UV radiation. The UV radiation may facilitate curing the coated optical fiber 122 to obtain an optical fiber 124.
In some aspects of the present disclosure, the optical fiber 124 may have a diameter that may be in a range of 150 micrometer (µm) to 250 µm. In some aspects of the present disclosure, the optical fiber 124 may have a diameter of any value without deviating from the scope of the present disclosure. In some aspects In some aspects of the present disclosure, the optical fiber 124 may be of any type without deviating from the scope of the present disclosure.
The capstan 112 may be coupled to the curing device 110. Specifically, the capstan 112 may be disposed downstream of the curing device 110. In other words, the optical fiber 124 may be transferred from the curing device 110 to the capstan 112. The capstan 112 may be adapted to pull the bare optical fiber 120 from the glass preform 118. Specifically, the capstan 112 may be adapted to rotate that may facilitate to pull the bare optical fiber 120 from the bottom of the glass preform 118. In some aspects of the present disclosure, the capstan 112 may be adapted to rotate by way of an external unit, for example, an electric motor.
In some aspects of the present disclosure, the capstan 112 may be a flexible belt that may be partially wounded over a flat pulley such that the flat pulley is adapted to rotate. Upon rotation of the flat pulley, the capstan 112 may be adapted to pull the bare optical fiber 120 from the bottom of the glass preform 118.
The idler pulley 114 may be disposed adjacent to the capstan 112. Specifically, the idler pulley 114 may be disposed downstream of the capstan 112. In other words, the optical fiber 124 may be transferred from the capstan 112 to the idler pulley 114. The idler pulley 114 may be adapted to generate a desired winding tension in the optical fiber 124.
Although FIG. 1 shows a single idler pulley i.e., the idler pulley 114, however, aspects of the present disclosure are intended to include and/or otherwise cover any number of idler pulleys, without deviating from the scope of the present disclosure. In such a scenario, each idler pulley of the number of idler pulleys may be configurationally, functionally, and structurally same or substantially similar to the idler pulley 114.
The take up spool 116 may be disposed adjacent to the idler pulley 114. Specifically, the take up spool 116 may be disposed downstream of the take up spool 116. In other words, the optical fiber 124 may be transferred from the idler pulley 114 to the take up spool 116. The idler pulley 114 may be adapted to generate the desired winding tension in the optical fiber 124 while the optical fiber 124 is wound over the take up spool 116. The take up spool 116 may therefore be adapted to collect the optical fiber 124.
FIG. 2 illustrates a side view of the cooling tube 106 of the optical fiber drawing system 100. The system 100 may further have a suction device 201. The cooling tube 106 may have a top end 202, a bottom end 204, a body portion 206, at least one inlet port 208, an input port 210, an outlet port 212, and at least one recovery port 214.
The top end 202 may be disposed at an upper side of the cooling tube 106 and the bottom end 204 may be disposed at a lower side of the cooling tube 106. The cooling tube 106 may extend from the top end 202 to the bottom end 204. The at least one inlet port 208 and the input port 210 may be disposed at the top end 202. The outlet port 212 and the at least one recovery port 214 may be disposed at the bottom end 204. The at least one recovery port 214 may be disposed near the bottom end 204 that may enhance effectiveness of the cooling tube 106. The at least one recovery port 214 may be disposed at the bottom end 204 as the at least one inert gas absorbs maximum heat of the bare optical fiber 120 while the at least one inert gas reaches to the bottom end 204. In some aspects of the present disclosure, the cooling tube 106 may have more than one inlet ports at different intermediate position along the along the longitudinal axis 218 of the cooling tube 106.
In some aspects of the present disclosure, the at least one recovery port 214 may be disposed anywhere between middle point 216 and the bottom end 204 along the longitudinal axis 218 of the cooling tube 106. In one aspect of the present disclosure, more than one recovery port 214 may be disposed between the middle point 216 and the bottom end 204 along the longitudinal axis 218 of the cooling tube 106. In an exemplary aspect of the present disclosure, when inert gas is injected via more than one inlet port 208, the cooling tube 106 may have more than one recovery port 218 to suck adequate flow of the inert gas relative to the supplied flow of the inert gas at the inlet ports 208. In some aspects of the present disclosure, the at least one recovery port 214 may be disposed nearly at 2/3rd of a vertical length position of the cooling tube 106. This may effectively cool the at least one inert gas and may facilitate to reinject the at least one inert gas back into the cooling tube 106. In some aspects of the present disclosure, the recovery of the inert gas may be started prior to the inert gas reaching the bottom end 204 of the cooling tube 106, because the inert gas becomes inefficient and may not contribute in cooling of the bare optical fiber 120 in the bottom region of the cooling tube 106. In an exemplary aspect of the present disclosure, the cooling rate of the bare optical fiber 120 inside the cooling tube 106 may be very low in the bottom 1/4th region along the longitudinal axis 218 of the cooling tube 106 and the cooling rate of the bare optical fiber 120 inside the cooling tube 106 may be very high in the top 3/4th region along the longitudinal axis 218 of the cooling tube 106. In an exemplary aspect of the present disclosure, the at least one recovery port 214 may be positioned at a 3/4th position along the longitudinal axis 218 of the total length of the cooling tube 106. In one example, if the total length of cooling tube 106 is x meters, the at least one recovery port 214 is positioned at 2X/3 meters (m) from the top end 210 of the cooling tube 106. When the recovery port is positioned at 2X/3 m from the top end 210 of the cooling tube 106, the inefficiency of heated inert gas in the bottom region of the cooling tube 106 may be avoided and the inert gas may be effectively recovered, cooled, and reinjected inside the cooling tube 106.
In some aspects of the present disclosure, more than one recovery port 214 may be placed at an intermittent interval below the middle point 216 and bottom end 204 along the longitudinal axis 218 of the cooling tube 106. The more than one recovery port 214 placed at the intermittent interval may help in fast recovery and recirculation of the at least one inert gas inside the cooling tube 106. In one example, if the total length of cooling tube 106 in longitudinal direction is x meters (m), the at least one recovery port 214 may be positioned between 2x/3 m to x/1000 m. In one more example, if the total length of cooling tube 106 in longitudinal direction is y meters (m), the at least one recovery port 214 may be positioned between 2x/3 m to x/100 m. In one example, if the total length of cooling tube 106 in longitudinal direction is y meters (m), the at least one recovery port 214 may be positioned between 2y/3 m to y/50 m. In one example, if the total length of cooling tube 106 in longitudinal direction is y meters (m), the at least one recovery port 214 may be positioned between 2y/3 m to y/10 m. The efficient positioning of one or more recovery port 214 is important to maintain tradeoff between effective utilization of the at least one inert gas as well as to avoid loss of the at least one inert gas from the exit portion of the cooling tube 106. In some aspects of the present disclosure, the cooling tube 106 may have any value of longitudinal length and any number of inlet ports 208 and any number of recovery ports 214 without deviating from the scope of the present disclosure.
The input port 210 may be adapted to accept the bare optical fiber 120. In other words, the bare optical fiber 120 may enter in the cooling tube 106 through the input port 210. Specifically, the input port 210 may be adapted to accept the bare optical fiber 120 from the annealing furnace 104. Upon entrance of the bare optical fiber 120 in the cooling tube 106, the at least one inert gas may be supplied in the cooling tube 106. Specifically, the at least one inert gas may be supplied in the cooling tube 106 through the at least one inlet port 208. Preferably, the at least one inert gas may be a helium gas. The at least one inert gas may be adapted to provide an inert environment inside the cooling tube 106. Specifically, the at least one inert gas may be adapted to provide the inert environment inside the cooling tube 106 while the cooling tube 106 lowers the temperature of the bare optical fiber 120. The at least one inert gas may advantageously avoid degradation of optical properties of the bare optical fiber 120. Specifically, the inert environment provided by the at least one inert gas may advantageously avoid degradation of the optical properties of the bare optical fiber 120. The at least one inert gas may advantageously avoid contact of the bare optical fiber 120 with walls of the cooling tube 106. Specifically, the inert environment provided by the at least one inert gas may advantageously avoid contact of the bare optical fiber 120 with walls of the cooling tube 106 while the bare optical fiber 120 is moved within the cooling tube 106. Thus, the at least one inert gas may advantageously prevent breaking of the bare optical fiber 120. Specifically, the at least one inert gas may advantageously prevent breaking of the bare optical fiber 120 while the bare optical fiber 120 is moved within the cooling tube 106 from the top end 202 to the bottom end 204. The at least one inert gas may further facilitate to lower the temperature of the bare optical fiber 120. In other words, the at least one inert gas may facilitate to cool the bare optical fiber 120. The cooling tube 106 may facilitate heat exchange between the at least one inert gas and the bare optical fiber 120. Specifically, the at least one inert gas may absorb heat of the bare optical fiber 120 and thereby lower the temperature of the bare optical fiber 120. In response to absorption of heat of the bare optical fiber 120, temperature of the at least one inert gas may be raised. The at least one inert gas may therefore become relatively hotter while exiting through the at least one recovery port 214.
In some aspects of the present disclosure, the volume of the at least one inert gas may be 10 m3. In other words, 10 m3 of the at least one inert gas may be supplied into the cooling tube 106. In some aspects of the present disclosure, the volume of at least one inert gas may be decided based on the total length of the cooling tube 106. In some aspects of the present disclosure, the entire volume of the at least one inert gas may be supplied at once or the at least one inert gas may be supplied in plurality of stages via plurality of inlet ports 208 for effective cooling and efficient recovery.
The outlet port 212 may be adapted to dispense the bare optical fiber 120. In other words, the bare optical fiber 120 may be ejected from the cooling tube 106 through the outlet port 212. The at least one recovery port 214 may facilitate to recover the at least one inert gas. Specifically, the at least one recovery port 214 may facilitate to recover the at least one inert gas when the at least one inert gas is supplied inside the cooling tube 106 through the at least one inlet port 208.
In some preferred aspects of the present disclosure, the at least one recovery port 214 may be positioned at an intermediate position along a longitudinal axis 218 of the cooling tube 106. The intermediate position along the longitudinal axis 218 is below a middle point 216 of the cooling tube 106. The intermediate position of the at least one recovery port 214 on the cooling tube 106 may facilitate to enhance recovery of the at least one inert gas. If the at least one recovery port 214 is placed exactly at a middle point 218 or above the middle point 218 of the cooling tube 106, the role of at least one inert gas may not be properly utilized in cooling of the bare optical fiber 120 and the cooling process becomes inefficient and more costly. In some aspects of the present disclosure, the intermediate position is at least 50 mm above the bottom end 212 of the cooling tube 106. In some aspects of the present disclosure, the intermediate position is at least 1/10th of the total length above the bottom end 212 of the cooling tube 106.
In some aspects of the present disclosure, the at least one recovery port 214 may enhance production rates of the optical fiber 124 without increasing consumption of the at least one inert gas.
In some aspects of the present disclosure, the at least one recovery port 214 may facilitate to recover at least 95% of the at least one inert gas from the at least one inert gas mixed with air inside the cooling tube.
The suction device 201 may be coupled to the cooling tube 106. Specifically, the suction device 201 may be disposed at the at least one recovery port 214. The suction device 201 may be adapted to generate a suction pressure at the at least one recovery port 214. Specifically, the suction device 201 may be adapted to generate the suction pressure at the at least one recovery port 214 to suck the at least one inert gas from the cooling tube 106. In response to the suction pressure, the at least one inert gas may be egressed or exit from the at least one recovery port 214. The at least one inert gas may be egressed or exit from the at least one recovery port 214 that may facilitate to recover the at least one inert gas from the cooling tube 106. In some preferred aspects of the present disclosure, the suction pressure may not be exceeded or increased beyond a certain value to avoid vibrations in the bare optical fiber 120 while the bare optical fiber 120 is inserted inside the cooling tube 106.
In some aspects of the present disclosure, while recovering the at least one inert gas from the at least one recovery port 214, at least 95% of the at least one inert gas may be recovered from the at least one recovery port 214. In one aspect of the present disclosure, the at least one recovery port 214 may be disposed at the bottom end 204 of the cooling tube 106 such that a ratio of a first distance to a second distance is greater than or equal to 1.5. The first distance may be a distance between the top end 202 of the cooling tube 106 and the at least one recovery port 214. The second distance may be a distance between the at least one recovery port 214 and the bottom end 204 of the cooling tube 106. The at least one recovery port 214 is not disposed parallel to the bottom end 204 because the role of inert gas in cooling the fiber in the bottom region is negligible and not efficient, so the inert gas may be recovered from an intermediate position along the longitudinal axis 218 of the cooling tube 106 and then reinjected after filtering and cooling of the inert gas. The intermediate position may be below the middle point 216 and significantly above the bottom end 204 of the cooling tube 106. If the recovery port 214 is placed parallel to the bottom end 204, the at least one inert gas may egress outside the cooling tube 106 and may lead to loss of the at least one inert gas.
In some aspects of the present disclosure, a third distance may be unequal to a fourth distance. The third distance may be a distance between the at least one input port 210 and the at least one recovery port 214. The fourth distance may be a distance between the at least one outlet port 212 and the at least one recovery port 214. Specifically, the third distance may be at least two times the fourth distance.
In some aspects of the present disclosure, the suction device 201 may be adapted to generate the suction pressure that may be in a range of -250 pascal to -5 pascal to suck the at least one inert gas. The suction pressure may be maintained between the disclosed range as per the present disclosure to avoid unnecessary suction of air from the outside environment or loss of the at least one inert gas.
In some aspects of the present disclosure, the suction device 201 may be any device that may create vacuum/negative pressure/suction at the at least one recovery port 214. For example, the suction device 201 may be a vacuum pump. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the suction device 201, without deviating from the scope of the present disclosure.
In some aspects of the present disclosure, a time difference between supplying of the at least one inert gas in the cooling tube 106 and recovering of the at least one inert gas may be less than one second.
FIG. 3 illustrates a side view of the cooling tube 106 with a choking device 300 of the optical fiber drawing system 100. In other words, the system 100 may further have the choking device 300. The choking device 300 may have an exit portion 302. The choking device 300 may be coupled to the cooling tube 106. The choking device 300 may act as an auxiliary hardware that may be coupled to the cooling tube 106. Specifically, the choking device 300 may be disposed at the bottom end 204 of the cooling tube 106. The choking device 300 may be inserted in the cooling tube 106. Specifically, the choking device 300 may be inserted from the outlet port 212. In other words, the choking device 300 may be adapted to choke the cooling tube 106. Specifically, the choking device 300 may be adapted to choke the cooling tube 106 from the outlet port 212. The choking device 300 may be adapted to prevent disturbance from external air. Specifically, the choking device 300 may prevent external air from entering the cooling tube 106 while the at least one inert gas maintains the inert environment inside the cooling tube 106. The choking device 300 may therefore advantageously facilitate to recover maximum amount of the at least one inert gas. Since, the choking device 300 chokes the cooling tube 106 and prevent entering of the external air into the cooling device 300, therefore, the choking device 300 advantageously facilitates to recover higher percentage of the at least one inert gas at higher rates. The exit portion 302 may be disposed at a bottom side of the choking device 300. The exit portion 302 may facilitate the bare optical fiber 120 to eject from the cooling tube 106 while the choking device 300 chokes the cooling tube 106 from the outlet port 212. The choking device 300 may further facilitate higher temperature drop across the length of the cooling tube 106.
In some aspect of the present disclosure, the effective placement of the intermediate recovery port 214 along with the reduced exit diameter of the choking device 300 may help in achieving recovery of at least 95 percent of the inert gas supplied from the inlet port 208.
In some preferred aspects of the present disclosure, the choking device 300 may have a converging-diverging nozzle shape. The converging-diverging nozzle shape of the choking device 300 facilitates in non-contact centering of the bare optical fiber 120. In some aspects of the present disclosure, the choking device 300 may have any other shape not limited to cube, nose cone, 3-d shape etc., without deviating from the scope of the invention.
In some aspects of the present disclosure, the exit portion 302 may have a diameter that may be in a range of 2 millimeters (mm) to 4.9 mm. In general, the opening diameter of the cooling tube 106 at the bottom end 212 is in a range of 8 mm to 10 mm. When suction of the inert gas at the at least one recovery port 214 is performed in absence of choking device 300 in the cooling tube 106, because of large opening at the bottom end 212 of the cooling tube 106, the suction device 201 may suck more amount of air from the outside environment form the opening of the bottom end 212. The exit portion 302 of the choking device has a reduced diameter (i.e., lesser diameter of opening at the bottom exit), the amount of air from the environment which get mixed with inert gas during suction is significantly reduced and recovered mixture at the recovery port 214 have higher purity of inert gas.
In some examples, 95% of the at least one inert gas may be recovered when the diameter of the exit portion 302 the choking device 300 is 2 mm. In some aspects of the present disclosure, effective positioning of the recovery port 214 at the intermediate position of the cooling tube 106 along with the reduced diameter of exit portion helps in achieving recovery of more than 95% of the at least one inert gas. In some other examples, 80% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 4 mm. In some other examples, less than 65% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 6 mm. In some other examples, about 43% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 8 mm. In some other examples, about 40% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 10 mm.
In some exemplary aspects of the present disclosure, about 94% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 2 mm. In some other examples, 77% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 4 mm. In some other examples, 60% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 6 mm. In some other examples, about 52% of the at least one inert gas may be recovered when the diameter of the exit portion 302 of the choking device 300 is 8 mm and 10 mm. In some aspects of the present disclosure, different combination of the diameter of exit portion 302 of the choking device 300 and the intermediate position of the recovery port 214 as per the present disclosure may achieve more than 95% recovery of the at least one inert gas.
In some aspects of the present disclosure, the choking device 300 may have a longitudinal length that may be in a range of 10 centimeters (cm) to 50 cm. In some aspects of the present disclosure, the choking device 300 may have the longitudinal length that may be in a range of 20 centimeters (cm) to 30 cm.
In some aspects of the present disclosure, the choking device 300 may be made up of a material that may be compliant with the cooling tube 106.
FIG. 4 illustrates a block diagram 400 of an intercooler device 402 for recovering a gas. Specifically, FIG. 4 illustrates the block diagram 400 of the intercooler device 402 for recovering the at least one inert gas in the system 100. The system 100 may further have an intercooler device 402. The intercooler device 402 may have a plurality of heat sinks 404a, 404b (hereinafter collectively referred to and designated as “the heat sinks 404”). The suction device 201 may generate the suction pressure at the at least one recovery port 214 to suck the at least one inert gas from the cooling tube 106. The suction device 201 may thereby facilitate to transfer the at least one inert gas from the cooling tube 106 to the intercooler device 402. The at least one inert gas may be passed through the intercooler device 402. Specifically, the at least one inert gas may be passed through the heat sinks 404 that may facilitate heat exchange for the at least one inert gas. Specifically, the heat sinks 404 may be adapted to lower the temperature of the at least one inert gas that may be egressed from the at least one recovery port 214. The at least one inert gas may be supplied back or injected back from the intercooler device 402 to the cooling tube 106. Specifically, the recovered at least one inert gas may be supplied back to the cooling tube 106 through the at least one inlet port 208. The intercooler device 402 may facilitate to enhance the thermodynamic potential of the at least one inert gas (helium) to extract heat from the bare optical fiber 120 due to higher temperature gradients.
Since recovered and intercooled helium is re-injected to the cooling tube is at lower temperature. Higher heat transfer rates for the same tube lengths
This may facilitate to utilize full potential of the at least one inert gas that may enable enhanced heat transfer between the bare optical fiber 120 and the at least one inert gas inside the cooling tube 106.
FIG. 5 illustrates a block diagram representing recovery and recirculation unit 500 of the optical fiber drawing system 100 of FIG. 1. In other words, the system 100 may further have the recovery and recirculation unit 500 to recover and recirculate the at least one inert gas in the system 100.
The recovery and recirculation unit 500 may have a first purity sensor 502, a first flow meter 504, a moisture removal device 506, a first buffer tank 508, a second buffer tank 510, a second purity sensor 512, a non-flow return valve 514, a supply tank 516, and a second flow meter 518.
The recovery and recirculation unit 500 may be adapted to receive a mixture of the at least one inert gas and the air (hereinafter referred to as “mixture”) from an inlet stream. In some aspects of the present disclosure, the recovery and recirculation unit 500 may be adapted to receive the mixture of the helium and the air from the inlet stream (hereinafter referred to as “mixture”). In some aspects of the present disclosure, the recovery and recirculation unit 500 may be adapted to receive the mixture of the helium, argon, and the air from the inlet stream The first purity sensor 502 may be adapted to receive the mixture from the inlet stream connected to the recovery port 214 of the cooling tube 106. The first purity sensor 502 may be adapted to measure concentration and purity of the inert gas in the mixture.
The first flow meter 504 may be coupled to the first purity sensor 502. Specifically, the first flow meter 504 may be disposed downstream of the first purity sensor 502. In other words, the mixture may be transferred from the first purity sensor 502 to the first flow meter 504. The first flow meter 504 may be adapted to measure flow of the mixture (in liter per minute) that may need to be taken from the cooling tube 106.
In some aspects of the present disclosure, the flow of the mixture taken from the at least one recovery port 214 may include same volume of the inert gas that may be injected from the at least one inlet port 208 of the cooling tube 106. In some aspects of the present disclosure, the flow of the mixture taken from the at least one recovery port 214 may include less volume of the inert gas that may be injected from the at least one inlet port 208 of the cooling tube 106.
The moisture removal device 506 may be coupled to the first flow meter 504. Specifically, the moisture removal device 506 may be disposed downstream of the first flow meter 504. In other words, the mixture may be transferred from the first flow meter 504 to the moisture removal device 506. The moisture removal device 506 may facilitate removing moisture from the mixture.
The first buffer tank 508 may be coupled to the moisture removal device 506. Specifically, the first buffer tank 508 may be disposed downstream of the moisture removal device 506. In other words, the mixture may be transferred from the moisture removal device 506 to the first buffer tank 508. The second buffer tank 510 may be coupled to the first buffer tank 508. Specifically, the second buffer tank 510 may be disposed downstream of the first buffer tank 508. In other words, the mixture may be transferred from the second buffer tank 510 to the first buffer tank 508.
The first and second buffer tanks 508, 510 may have compressors, filters, and pressure sensors. The compressors may compress the mixture. The filters may remove impurities from the mixture (primarily air is removed from the mixture). The pressure sensors may be configured to determine pressure of the mixture in the first and second buffer tanks 508, 510. The first and second buffer tanks 508, 510 may facilitate filtering of the mixture in separate stages i.e., the first stage and the second stage. Specifically, the first buffer tank 508 may facilitate filtering the mixture in the first stage and the second buffer tank 510 may facilitate filtering the mixture in the second stage. Upon filtering of the mixture in the first and second stages, the filtered mixture (i.e., the inert gas such as helium) may be stored in the first and second buffer tanks, separately.
The second purity sensor 512 may be coupled to the second buffer tank 510. Specifically, the second purity sensor 512 may be disposed downstream of the second buffer tank 510. In other words, the mixture may be transferred from the second buffer tank 510 to the second purity sensor 512. The second purity sensor 512 may measure the purity and concentration of the helium in the mixture.
The non-flow return valve 514 may be coupled to the second purity sensor 512. Specifically, the non-flow return valve 514 may be disposed downstream of the second purity sensor 512. In other words, the mixture may be transferred from the second purity sensor 512 to the non-flow return valve 514. Once sufficient amount of the helium is separated, the non-flow return valve 514 may be opened to store the recovered helium in the supply tank 516, where cooling of the helium is done. In other words, once the purity of helium is achieved, the non-flow return valve 514 may be opened to store the recovered helium in the supply tank 516. If the second purity sensor 512 detects the purity or concentration of helium is less (i.e., sufficient amount of air is still present in the mixture), the non-flow return valve 514 may remain closed and the mixture is recirculated back for purification and separation of air from the mixture.
The supply tank 516 may be coupled to the non-flow return valve 514. Specifically, the supply tank 516 may be disposed downstream of the non-flow return valve 514. In other words, the mixture may be transferred from the non-flow return valve 514 to the supply tank 516. The supply tank may be adapted to store and supply the recovered helium.
The second flow meter 518 may be coupled to the supply tank 516. Specifically, the second flow meter 518 may be disposed downstream of the supply tank 516. In other words, the mixture may be transferred from the supply tank 516 to the second flow meter 518. The second flow meter 518 may be adapted to measure the flow of the recovered helium that may be supplied back to the cooling tube.
The flow monitoring at the first flow meter 504 is very crucial because if the flow is too high (suction of the mixture at high speed), then high vibrations may be produced inside the cooling tube 106. The high vibrations may subsequently lead to degradation of the optical properties of the bare optical fiber 120 or may cause the break of the bare optical fiber 120. If the flow is too low (suction of the mixture at low speed) may lead to loss of helium as the helium may go outside from the bottom end of the cooling tube 106.
Once the helium is cooled and ready for supply, the helium may be provided via an outlet stream to supply again in the cooling tube 106 with desired flow (in liter per minute). The recovered and recirculated helium that may be supplied back may have 99.99 percent concentration (i.e., purity) of the helium.
FIG. 6 illustrates a flowchart of a method 600 for drawing the optical fiber 124. Specifically, FIG. 6 illustrates the flowchart of the method 600 for drawing the optical fiber 124 from the system 100. The method 600 may facilitate to efficiently recover the at least one inert gas such as helium from the cooling tube 106 while cooling of the optical fiber 124 during drawing of the optical fiber 124. The method 600 may have following steps for drawing the optical fiber 124 from the system 100.
At step 602, the glass preform 118, by way of the system 100, may be melted. Specifically, the glass preform 118 may be melted by way of the draw furnace 102 to obtain the bare optical fiber 120. The draw furnace 102 may be disposed at an upper side of the system 100. The draw furnace 102 may be adapted to receive a cylindrical glass preform 118 (hereinafter referred to and designated as “the glass preform 118”). The draw furnace 102 may have a hollow chamber (not shown) that may be adapted to accept the glass preform 118. Specifically, the glass preform 118 may be inserted through a first cylindrical portion (not shown) of the hollow chamber such that the glass preform 118 ejects from a second cylindrical portion (not shown) of the hollow chamber. The draw furnace 102 may further be adapted to raise temperature of the glass preform 118 that facilitates melting of the glass preform 118. The glass preform 118, upon melting, may facilitate generation of the bare optical fiber 120. The bare optical fiber 120 may be drawn from the draw furnace 102.
At step 604, the bare optical fiber 120 may be inserted into the cooling tube 106. The bare optical fiber 120 may be inserted into the cooling tube 106 through the top end 202 of the cooling tube 106. Specifically, the bare optical fiber 120 may be inserted into the cooling tube 106 through the top end 202 at a first temperature.
At step 606, the bare optical fiber 120, by way of the system 100, may be cooled. Specifically, the bare optical fiber 120 may be cooled by way of the cooling tube 106. The cooling tube 106 may be coupled to the annealing furnace 104. Specifically, the cooling tube 106 may be disposed downstream of the annealing furnace 104. In other words, the bare optical fiber 120 may be transferred from the annealing furnace 104 to the cooling tube 106. The cooling tube 106 may be adapted to receive the bare optical fiber 120 that may be annealed by the annealing furnace 104. The cooling tube 106 may be adapted to lower the temperature of the bare optical fiber 120. In other words, the cooling tube 106 may be adapted to cool down the bare optical fiber 120 after annealing the bare optical fiber 120. The cooling tube 106 may be adapted to cool down the bare optical fiber 120 by passing at least one cooling fluid or at least one inert gas through the cooling tube 106. Specifically, to cool down the bare optical fiber 120, the cooling tube 106 may facilitate contact of the at least one cooling fluid or the at least one inert gas with the bare optical fiber 120. In other words, when the at least one cooling fluid or the at least one inert gas may come in contact with the bare optical fiber 120, the temperature of the bare optical fiber 120 is reduced. Thus, the at least one cooling fluid or the at least one inert gas may facilitate cooling of the bare optical fiber 120.
At step 608, the at least one inert gas may be supplied in the cooling tube 106. Specifically, the at least one inert gas may be supplied in the cooling tube 106 through the at least one inlet port 208. Preferably, the at least one inert gas may be a helium gas. The at least one inert gas may be adapted to provide an inert environment inside the cooling tube 106. Specifically, the at least one inert gas may be adapted to provide the inert environment inside the cooling tube 106 while the cooling tube 106 lowers the temperature of the bare optical fiber 120. The at least one inert gas may advantageously avoid degradation of optical properties of the bare optical fiber 120. Specifically, the inert environment provided by the at least one inert gas may advantageously avoid degradation of the optical properties of the bare optical fiber 120. The at least one inert gas may advantageously avoid contact of the bare optical fiber 120 with walls of the cooling tube 106. Specifically, the inert environment provided by the at least one inert gas may advantageously avoid contact of the bare optical fiber 120 with walls of the cooling tube 106 while the bare optical fiber 120 is moved within the cooling tube 106. Thus, the at least one inert gas may advantageously prevent breaking of the bare optical fiber 120. Specifically, the at least one inert gas may advantageously prevent breaking of the bare optical fiber 120 while the bare optical fiber 120 is moved within the cooling tube 106 from the top end 202 to the bottom end 204. The at least one inert gas may further facilitate to lower the temperature of the bare optical fiber 120 by extracting the heat from the bare optical fiber 120. In other words, the at least one inert gas may facilitate to cool the bare optical fiber 120. The cooling tube 106 may facilitate heat exchange between the at least one inert gas and the bare optical fiber 120. Specifically, the at least one inert gas may absorb heat of the bare optical fiber 120 and thereby lower the temperature of the bare optical fiber 120. In response to absorption of heat of the bare optical fiber 120, temperature of the at least one inert gas may be raised. The at least one inert gas may therefore become relatively hotter while exiting through the at least one recovery port 214. If the at least one inert gas is not recovered, the at least one inert gas may egress from the bottom end 204 of the cooling tube 106.
At step 610, the cooling tube 106 may be choked. Specifically, the cooling tube 106 may be choked by way the choking device 300. The choking device 300 may act as an auxiliary hardware that may be coupled to the cooling tube 106. Specifically, the choking device 300 may be disposed at the bottom end 204 of the cooling tube 106. The choking device 300 may be inserted in the cooling tube 106. Specifically, the choking device 300 may be inserted from the outlet port 212. In other words, the choking device 300 may be adapted to choke the cooling tube 106. Specifically, the choking device 300 may be adapted to choke the cooling tube 106 from the outlet port 212. The choking device 300 may be adapted to prevent disturbance from the external air. Specifically, the choking device 300 may prevent the external air from entering the cooling tube 106 while the at least one inert gas maintains the inert environment inside the cooling tube 106.
At step 612, the system 100 may be adapted to generate the suction pressure. Specifically, the system 100, by way of the suction device 201, may be adapted to generate the suction pressure at the cooling tube 106. The suction device 201 may be coupled to the cooling tube 106. Specifically, the suction device 201 may be disposed at the at least one recovery port 214. The suction device 201 may be adapted to generate the suction pressure at the at least one recovery port 214. Preferably, the suction device 201 may be adapted to generate the suction pressure at the at least one recovery port 214. Specifically, the suction device 201 may be adapted to generate the suction pressure at the at least one recovery port 214 to suck the at least one inert gas from the cooling tube 106. In response to the suction pressure, the at least one inert gas may be egressed or exit from the at least one recovery port 214. The at least one inert gas may be egressed or exit from the at least one recovery port 214 that may facilitate to recover the at least one inert gas from the cooling tube 106. In some preferred aspects of the present disclosure, the suction pressure may not be exceeded or increased beyond a certain value to avoid vibrations in the bare optical fiber 120 while the bare optical fiber 120 is inserted inside the cooling tube 106.
At step 614, the at least one inert gas may be recovered from the system 100. Specifically, the at least one inert gas may be recovered from the at least one recovery port 214. The at least one recovery port 214 may facilitate to recover the at least one inert gas from the mixture (at least one inert gas and air) when the at least one inert gas is supplied inside the cooling tube 106 through the at least one inlet port 208. The air may ingress inside the cooling tube 106 from the opening at the top end 202 of the cooling tube 106. In some aspects of the present disclosure, the at least one recovery port 214 may be positioned at the intermediate position along the longitudinal axis 218 of the cooling tube 106. The intermediate position may be below the middle point 216 and above the bottom end 204 of the cooling tube 106.
In some aspects of the present disclosure, the time difference between the step 608 and the step 614 may be less than one second. Specifically, the time difference between supplying of the at least one inert gas and recovering the at least one inert gas may be zero.
At step 616, the cooled bare optical fiber 120, by way of the system 100, may be coated to obtain the optical fiber 124. Specifically, the cooled optical fiber may be coated by way of the coating apparatus 108 to obtain the optical fiber 124. The coating apparatus 108 may be coupled to the cooling tube 106. Specifically, the coating apparatus 108 may be disposed downstream of the cooling tube 106. In other words, the bare optical fiber 120 may be transferred from the cooling tube 106 to the coating apparatus 108. The one or more coating devices may be adapted to apply a coating layer on the bare optical fiber 120. Specifically, the one or more coating devices may be adapted to coat the bare optical fiber 120 with one or more primary coating materials and one or more secondary coating materials to generate a coated optical fiber 122. The one or more primary coating materials and the one or more secondary coating materials may be adapted to protect the surface of the bare optical fiber 120. Thus, the one or more primary coating materials and the one or more secondary coating materials may advantageously facilitate to improve strength of the bare optical fiber 120. The one or more primary coating materials and the one or more secondary coating materials may be excellent in terms of heat resistance, cold resistance, and may demonstrate stable function over a wide temperature range. Thus, the one or more primary coating materials and the one or more secondary coating materials may protect the coated optical fiber 122 from cracks and thus makes the coated optical fiber 122 resistant to abrasion and scratches.
At step 618, the optical fiber 124 may be extracted. Specifically, the optical fiber 124 may be extracted from the bottom end 204 of the cooling tube 106 at a second temperature. Preferably, the second temperature may be less than the first temperature. Specifically, the second temperature may be at least 60% less than the first temperature.
Thus, the system 100 may advantageously enhance speed of drawing of the optical fiber 124. Specifically, the system 100 may advantageously facilitate to draw the optical fiber 124 up to 20% higher speed as compared to speed of drawing an optical fiber from conventional apparatus. In general, the speed of drawing an optical fiber in conventional apparatus is in a range of 1800 to 2000 meter per minute. The system 100 may advantageously enhance recovery of the at least one inert gas. Comparatively, the system 100 may advantageously recover at least 95 % of the at least one inert gas (i.e., helium) supplied via the inlet port 208. The system 100 may advantageously eliminate losses while drawing the optical fiber 124.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within scope of the embodiments as described herein.
While several possible aspects of the invention have been described above and illustrated in some cases, it should be interpreted and understood as to have been presented only by way of illustration and example, but not by limitation. Thus, the breadth and scope of a preferred aspect should not be limited by any of the above-described exemplary aspects.
, Claims:CLAIMS

We Claim:
1. A method (600) for drawing an optical fiber (124), the method (600) comprising:
melting a cylindrical glass preform (118) in a draw furnace (102) to obtain a bare optical fiber (120);
cooling the bare optical fiber (120) inside a cooling tube (106), where the cooling tube (106) comprises at least one inlet port (208) and at least one recovery port (214);
supplying at least one inert gas inside the cooling tube (106) from the at least one inlet port (208);
recovering the at least one inert gas from the at least one recovery port (214), where the at least one recovery port (214) is positioned at an intermediate position along a longitudinal axis (218) of the cooling tube (106), where the intermediate position is above a bottom end (212) and below a middle point (216) of the cooling tube (106); and
coating the cooled bare optical fiber (120) to obtain the optical fiber (124).
2. The method (600) of claim 1, where prior to recovering, the at least one inert gas from the at least one recovery port (214), the method (600) further comprising chocking the cooling tube (106) by way of a chocking device (300) that is disposed at a bottom end (204) of the cooling tube (106).

3. The method (600) of claim 2, where the chocking device (300) comprises an exit portion (302) such that a diameter of the exit portion (302) is in a range of 2 millimeters (mm) to 4.9 mm.
4. The method (600) of claim 2, where the chocking device (300) has a longitudinal length that is in a range of 10 centimeters (cm) to 50 cm.
5. The method (600) of claim 2, where the chocking device (300) has a converging-diverging nozzle shape.
6. The method (600) of claim 1, where, while recovering the at least one inert gas from the at least one recovery port (214), at least 95% of the at least one inert gas is recovered from the at least one recovery port (214), where the at least one recovery port (214) is disposed at a bottom end (204) of the cooling tube (106) such that a ratio of a first distance to a second distance is greater than or equal to 1.5.
7. The method (600) of claim 1, where a time difference between supplying of the at least one inert gas and recovering of the at least one inert gas is less than one second.
8. The method (600) of claim 2, where upon chocking and prior to recovering, the method (600) further comprising generating, by way of by way of a suction device (201) that is coupled to the at least one recovery port (214), a suction pressure in a range of -250 pascal to -5 pascal to suck the at least one inert gas.
9. The method (600) of claim 1, where prior to cooling the bare optical fiber (120) inside the cooling tube (106), the method (600) further comprising inserting the bare optical fiber (120) from a top end (202) of the cooling tube (106) at a first temperature.
10. The method (600) of claim 1, where upon coating the cooled bare optical fiber (120), the method (600) further comprising extracting the optical fiber (124) from a bottom end (204) of the cooling tube (106) at a second temperature, where the second temperature is at least 60% less than the first temperature.
11. The method (600) of claim 1, where a third distance is unequal to a fourth distance such that the third distance is at least two times of the fourth distance, where the third distance is a distance between the at least one input port (210) and the at least one recovery port (214) and the fourth distance is a distance between at least one outlet port (212) and the at least one recovery port (214).
12. The method (600) of claim 1, where the intermediate position is at least 50 mm above the bottom end (212) of the cooling tube (106).