WO2001017887A1

WO2001017887A1 - Passive tension regulator for optical fiber winder

Info

Publication number: WO2001017887A1
Application number: PCT/US2000/020122
Authority: WO
Inventors: David A. Bednarczyk; Richard E. Blazek; Marcos G. Oritz; Massoud Rahiminejad
Original assignee: Corning Incorporated
Priority date: 1999-09-07
Filing date: 2000-07-24
Publication date: 2001-03-15
Also published as: AU6748300A

Abstract

An optical fiber winder comprises a frame and an array of pulleys for guiding fiber (12a) from a fiber source to a takeup spool (14a), each of the pulleys in the array being mechanically linked to the frame. The array of pulleys includes a regulator pulley (36) linked to the frame by a passive tension regulating element (38), the regulator pulley providing a fiber buffer for high frequency tugs on the fiber being wound onto the takeup spool, the regulator pulley further limiting tension oscillations in the fiber being wound onto the takeup spool.

Description

PASSIVE TENSION REGULATOR FOR OPTICAL FIBER WINDER

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to improvements to systems and

methods for winding optical fiber onto a spool, and more particularly to aspects of a

system and methods for regulating the tension of optical fiber as it is wound onto a

spool.

Description of the Prior Art

Optical fiber is typically packaged by winding it from a bulk spool onto a takeup

spool using a high-speed winding machine. However, in currently used fiber winding

systems, the geometry of the takeup spool and the winding pattern leads to undesirable

tension spikes in the fiber as it is being wound onto the spool. These tension spikes can

lead to improper winding of the fiber which in turn can lead to damage to the fiber,

resulting in inferior performance or even product failure.

Some tension control is provided in current systems through the use of a dancer

pulley and by controlling the speed at which the takeup spool is rotated. However, these control mechanisms are inadequate to eliminate tension spikes of relatively small magnitude and short duration.

There is thus a need for an optical fiber winding system that addresses the issue of high-frequency tension spikes.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to an optical fiber winder comprising

a frame and an array of pulleys for guiding fiber from a fiber source to a takeup spool,

each of the pulleys in the array being mechanically linked to the frame. The array of

pulleys includes at least a first regulator pulley linked to the frame by a passive tension

regulating element, the regulator pulley providing a fiber buffer for high frequency tugs

on the fiber being wound onto the takeup spool, the regulator pulley further limiting

tension oscillations in the fiber being wound onto the takeup spool. In one

embodiment, the passive tension regulating element comprises a spring. Alternatively,

the passive tension regulating element may comprise a pressurized air pocket at the axle

of the regulator pulley.

This passive tension regulating element is preferably utilized in conjunction

with another, second tension regulating element. The second tension regulating

element also preferably includes a pulley which the fiber is in contact with. The second

fiber tension regulating element is preferably designed to regulate the fiber draw tension

against tension variations in the fiber which are of higher magnitude than the tension

variations regulated by the first tension regulating element. The second fiber tension

regulating element may be, for example, a dancer pulley which preferably operates

either continuously or intermittently in a passive mode. Preferably, the second fiber

tension regulating element has a spring constant or tension applied thereto in a direction which imparts the tension to the fiber being drawn, the spring constant or tension being

of higher magnitude than the spring constant or tension applied to the first passive

tension regulating element. In this way, the second tension regulating device can be

designed to mitigate against relatively larger variations in the fiber draw tension, while

the first passive tension is designed to mitigate against relatively smaller variations in

the fiber draw tension. The second tension regulating device may also include a closed

control feedback to either the amount of tension applied to the second tension

regulating device, or the speed with which the fiber is being wound onto the spool. In

a preferred embodiment, the tension applied by said second fiber tension regulating

element or the speed with which said fiber is being wound is periodically adjusted in

response to a change in tension in said fiber being wound. For example, the periodic

adjustment can be in response to a change in tension in the fiber which is caused by the

fiber spool becoming more full. Consequently, in this embodiment, the second tension

regulating device operates during certain periods as a totally passive device, while at

other times (e.g., when the applied tension or the fiber winding speed is being altered) it

acts as part of an active controlled device. In this way. the magnitude of the spring or

other device which is employed to apply tension to the first tension regulator can be

chosen to mitigate against variations in fiber tension which are not appreciably

mitigated against by the second tension regulating device.

The array of pulleys employed in the optical fiber winding device may include

first and second guide pulleys, wherein the fiber is threaded in alternate directions

around the first guide pulley, one of the regulator pulleys, and the second guide pulley. These first and second guide pulleys can be linked to the frame by stiff supports. The

spring is preferably chosen according to the magnitude of allowable variation in fiber

tension and the magnitude of expected tugs on the fiber. The array of pulleys may also include a guide pulley, wherein the fiber is threaded in alternate directions around the

guide pulley and the regulator pulley.

The optical fiber winder may further include a tension-sensing device attached

to one or both of the tension regulating devices, for providing fiber tension information

to a controller in a feedback control loop. For example, these tension regulators may

include the regulator pulley being linked to the frame by a pneumatic piston, the

elasticity of which is a function of the air pressure within the piston, and wherein the

controller adjusts the elasticity of the piston by increasing or decreasing the air pressure

within the piston.

Another aspect of the invention relates to a method for winding optical fiber,

which comprises the steps of guiding fiber from a fiber source to a takeup spool using

an array of pulleys, each of the pulleys in the array being mechanically linked to a

supporting frame, one of the pulleys in the array being a regulator pulley that is linked

to the frame by a passive tension regulating element. The regulator pulley acts as a

fiber buffer for high frequency tugs on the fiber being wound onto the takeup spool and

limiting tension oscillations in the fiber being wound onto the takeup spool. The

method may be facilitated using the fiber winding apparatus described above and

further hereinbelow. Thus, for example, the high frequency tension regulating element

is preferably utilized in conjunction with another, second tension regulating element, as

described above with respect to the apparatus.

A more complete understanding of the present invention, as well as further

features and advantages of the invention, will be apparent from the following detailed

description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a diagram of an optical fiber winding system according to the prior

art.

Fig. 2 shows a cross section of a takeup spool that has been partially wound

with optical fiber.

Fig. 3 shows a plan view of consecutive layers of optical fiber that have been wound onto a takeup spool.

Fig. 4 shows a diagram of a first embodiment of an optical fiber winding system

employing a passive tension regulator according to the present invention.

Fig. 5 shows a first embodiment of a pulley array employing a passive tension regulator according to the present invention.

Fig. 6 shows a further embodiment of a pulley array employing a passive

tension regulator according to the present invention.

Fig. 7 shows a perspective view of a first embodiment of a passive tension

regulator pulley according to the present invention.

Fig. 8 shows a further embodiment of an optical fiber winding system

employing a passive tension regulator according to the present invention.

Fig. 9 shows a diagram of a takeup wing for use in an optical fiber winding

system according to the prior art.

Fig. 10 shows a diagram of a takeup wing for use in an optical fiber winding

system according to the present invention.

Fig. 1 1 shows a graph comparing measured optical fiber tension at the takeup spool in a system in an optical fiber winding according to the prior art and in an optical

fiber winding system according to the present invention. Fig. 12 shows a diagram of an alternative embodiment of an optical fiber

winding system according to the present invention.

DETAILED DESCRIPTION The present invention now will be described more fully with reference to the

accompanying drawings, in which currently preferred embodiments of the invention are

shown. However, the described invention may be embodied in various forms and

should not be construed as limited to the exemplary embodiments set forth herein.

Rather, these representative embodiments are described in detail so that this disclosure

will be thorough and complete, and will fully convey the structure, operation,

functionality and potential scope of applicability of the invention to those skilled in the

art.

Fig. 1 shows a diagram of a typical optical fiber winding system 10 according to

the prior art. Optical fiber 12 from a fiber source, such as a bulk spool, is fed to a

takeup spool 14 by a series of pulleys 16, 18, 20. Pulleys 16 and 20 are mounted to the

frame of the fiber winding machine using fixed supports. Pulley 18 is mounted to a

dancer arm 22 that moves in a circular path around a pivot armature 24, discussed in

detail below.

The takeup spool 14 is mounted onto a spindle assembly that rotates the spool

around its longitudinal axis. The spindle assembly in turn is mounted to a traverse

assembly that moves the rotating spool back and forth along its longitudinal axis. The

combined movements of the spindle and traverse assemblies relative to the incoming

fiber 12 causes the fiber to be wound back and forth onto the barrel of the spool 14 in

layers in a close helical pattern. It is desirable for the optical fiber 12 to be wound onto the takeup spool 14 as

accurately as possible in order to prevent damage to the fiber. Further, the quality of

the wind greatly affects the ease with which fiber is unwound from the spool, and

thereby the effective use of the fiber. The quality of the wind is affected by a number of

parameters, including the speed of the spindle and traverse assemblies and the tension

of the fiber 12 as it is laid onto the takeup spool 14.

In order to maintain a constant linear speed for winding fiber 12 onto the spool

14, the spindle rotational speed must vary according to the diameter of the barrel of the

spool. However, this diameter varies with the amount of fiber that has already been

wound onto the spool. This is illustrated in Fig. 2, which shows a cross section of the

top half of a partially wound takeup spool 14. It should be noted that Fig. 2 is not

drawn to scale. As shown in Fig. 2, the fiber 12 is wound around the spool barrel 26

between a pair of flanges 28, in a series of layers 12a-e. The diameter of the winding

surface increases in steps, with each new layer of fiber wound onto the spool barrel 26.

This can be appreciated by a visual comparison of radii 30 and 32.

Thus, in order to accommodate this stepwise increase in the diameter of the

winding surface, variations in the spindle speed typically occur in steps, with each new

layer of fiber wrapped onto the spool. Returning to Fig. 1, the dancer pulley 18 is

provided to accommodate these variations in speed by creating a buffer of fiber that

provides the extra fiber required to maintain a constant linear speed while the rotational

speed is varying.

In the prior art system shown in Fig. 1 , in addition to providing a buffer of

optical fiber, the dancer pulley 18 performs the functions of setting the tension of the

fiber 12 and providing a signal to a rotational speed controller that the spindle speed

needs to be adjusted. A brush DC motor (not shown), includes a pivot armature 24, which extends out of both ends of the DC motor. One end of pivot armature 24 connects to dancer arm 22, and applies a constant torque to the dancer arm 22 in a

counterclockwise direction. The tension in the optical fiber 12 threaded through the

pulley applies torque to the dancer arm 22 in a clockwise direction. The torque applied

by the DC motor balances the torque applied by the tension of the optical fiber. During

the initialization of the winding machine 10, there is established a setpoint position of

the dancer arm 22, which is the dancer arm position representing an optimal amount of

tension in the optical fiber being wound onto the takeup spool 14.

The position of the dancer arm 22 is detected by a suitable position sensing

device, such as a rotary variable differential transformer (RVDT). The RVDT is

connected to the other end of armature 24, which extends from the DC motor. Thus,

one end of armature 24 connects to dancer arm 22, while the other end of armature 24

connects to the RVDT. When dancer arm 22 moves about armature 24, armature 24 is

caused to rotate. This rotation is sensed by the RVDT, causing the RVDT to generate a

voltage signal that bears a linear relationship to the amount of shaft rotation, and thus

the amount of movement of dancer arm 22. A microprocessor controller (not shown)

determines the position of the dancer arm 22 by monitoring the RVDT voltage signal.

The position of the dancer arm is, of course, directly related to the amount of tension in

the fiber being wound onto the spool.

Each dancer arm position corresponds to a different level of tension in the

optical fiber 12. When the tension of the fiber 12 falls below the optimal level, the

dancer arm 22 will swing away from the dancer setpoint in a counterclockwise direction

to a new position to the left of the setpoint, the new position indicating the lower

tension level. When the tension of the fiber 12 rises above the optimal value, the

dancer arm 22 will swing away from the dancer setpoint in a clockwise direction to a new position to the right of the setpoint, the new position indicating the higher tension

level. The speed of rotation of the takeup spool is adjusted in response to the position

of the dancer arm. In this way, the speed with which the fiber is wound onto the takeup

spool or the torque which is applied to the fiber via the dancer arm is adjusted so that

the dancer is preferably maintained within a range of positions adjacent a vertical

position, thereby maintaining a substantially uniform winding tension of the fiber onto

the takeup spool. The tension of the fiber 12 is a function of a number of variables, including the takeup spool diameter and the rotational speed of the spool.

The RVDT and its associated microprocessor controller are used to maintain the

dancer arm 22 in a vertical position. The vertical position of the dancer arm 22 tends to

minimize the effects of gravity. However, although feedback is used to maintain dancer

arm 22 within an appropriate tension range so that it moves with a range of positions

around a vertical position, at times between such adjustments to the speed of the takeup

spool, the dancer arm 22 operates essentially as a passive device that floats back and

forth depending upon the changing tension of the optical fiber 12.

The layer-to-layer diameter difference described above is not the only source of

demands on fiber length and tension control in the system. Because the fiber is wound

in a helical pattern that alternates from one layer to the next, the fiber package does not

have a uniform diameter, even within one revolution of its circumference. This is

illustrated in Fig. 3, which is a side view of optical fiber 12 that has been partially

wound onto the takeup spool 14. It should be noted that Fig. 3 is not drawn to scale.

As shown in Fig. 3, a layer of fiber has been laid down, and a new layer is being started

with the fiber end 12f. Because the optical fiber 12 has a round profile, a layer of fiber

is not flat, but rather has alternating "hills" and "valleys." Thus, as the new layer of

fiber is laid down over the previous layer, the fiber crosses over hills and become depressed into valleys. Crossovers are illustrated as intersection points 34 between the

fiber end 12f and fiber already laid down onto the spool. Depressions occur in between crossover points.

Crossovers and depressions occur at a rate of two per revolution. These regular

and inherent spool variations account for periodic tugs experienced by the fiber in the

system, and which result in tension oscillations. Because these tugs are of relatively

small magnitude, short duration, and high frequency, it is not practical to regulate these

periodic tugs by adjusting the spool rotational speed.

In the system shown in Fig. 1 , the periodic tugs are felt by both the package and

by the dancer, in the form of tension oscillations. However small they may be, these

oscillations nonetheless affect the dancer position and thus may lead to unnecessary

control actions that can lead to instability of the whole process. During fiber winding,

these tension oscillations can also affect the package, causing the fiber wound onto the

package to become distorted. In particular, high tension spikes can cause the fiber to

bury itself deep within the layers of fiber already laid onto the spool. Low tension

spikes can result in loops of loose fiber becoming trapped in the wind. Both results are

undesirable. Buried fiber is hard to unwind and can lead to a break. Fiber loops often

show up as local anomalies, potentially leading to poor optical performance of the fiber.

The present invention addresses the above-described disadvantages of the prior

art by providing a passive means that increases, or sets to a specific design value, the

compliance of the fiber winder, thereby making it more elastic or easier to elongate.

The present invention can also be used to regulate the tension in a payout situation,

such as in cabling line or during rewinding. Preferably, the passive tension regulator is

used in conjunction with an active tension regulator such as the dancer arm 22

described above. The purpose of this system compliance is to enable the system to absorb sudden and short duration tugs on the fiber, or the regular periodic tugging that

occurs at relatively high frequency, without affecting its operation and preventing large

fluctuations of the fiber tension.

Fig. 4 shows a first embodiment of a system 10a according to the present

invention. In the depicted system 10a, a passive tension regulator pulley 36 has been

introduced between pulley 20a and the takeup spool 14a. The regulator pulley 36 is

linked to the frame of the fiber winder using a spring 38 connected to a stiff support 40.

As described further below, it would also be within the spirit of the present invention to

use a pressurized air pocket, such as that shown in Fig. 7 and discussed below, in place

of spring 38. The choice of which component to use depends upon considerations of

available space in the fiber winder and component reliability.

The passive tension regulator pulley 36 assumes the fiber buffer function for

high frequency tugs, such as those resulting from crossovers and depressions in winding

a new layer of fiber onto a previously wound layer on the barrel of spool 14a. The

passive tension regulator pulley 36 and the dancer 18a create analogous structures in the

fiber path. The mass of the regulator pulley 36 and the characteristics of the spring 38

are chosen to react more quickly than the dancer 18a to the high frequency tugs. The

low frequency tugs, like the ones due to an increase or decrease of spool diameter from

one layer of fiber to the next, still reach the dancer 18a. Further, the passive tension

regulator pulley 36 limits the tension oscillations seen by the dancer 18a and the spool

package 14a to a designed magnitude. The characteristics of the spring 38 are chosen

according to the desired range of variation. Experiments have shown that the use of a

passive tension regulator pulley in accordance with the present invention can reduce

tension variations in the winder by a factor of two. The passive tension regulator pulley 36 in the fiber path provides a number of

benefits. First, tension oscillations are reduced to a desired level. Without the regulator

pulley 36, measured tension spikes can be larger than the nominal tension itself.

Second, as a result of reduced tension oscillations, the dancer 18a is steadier and the

spindle speed that it controls is also better behaved. Third, the resulting spool package

appears smoother to the naked eye and consistently shows less wind-induced defects

(for example, optical attenuation) than a regular package wound in a winder without the passive tension regulator. Fourth, the resulting spool package has fewer instances of

buried fiber and unwinds more easily.

A passive tension regulator pulley can also be used in a fiber payout

configuration, that is, in a situation in which fiber is unwound from a spool. The

tension regulator pulley in a payout configuration makes the system more tolerant of

poorly wound fiber spool, because it absorbs the high-frequency defects associated with

a poor winding.

Fig. 5 shows a further embodiment of a passive tension regulator system 42

according to the present invention. In the embodiment depicted in Fig. 5, the system 30

comprises an array of pulleys 44, 46, 48 defining a path for optical fiber 50. Guide

pulleys 44 and 48 are mounted to the frame of the optical fiber winder using stiff

supports 52, 54. Regulator pulley 46 is linked to the frame of the fiber winding using

an elastic or compliant element 56. Element 56 can be provided, for example, by a

spring or alternatively a pressurized air pocket.

In prior-art systems, which lack a regulator pulley, high-frequency tugs on the

fiber caused by non-uniformities of the fiber spool package to which the fiber is being

wound or from which the fiber is being paid out have to be absorbed by the fiber

package itself. A fiber package typically exhibits the physical properties of a relatively stiff spring. Therefore, these high-frequency tugs result in large tension spikes in the

fiber. By using one or more regulator pulleys having softened links to the frame of the

fiber winder, as shown in Fig. 5, the regulator pulleys absorb the tugs and thereby

regulate the fiber tension. The spring used to link the regulator pulley to the frame of

the fiber winder is chosen according to the magnitude of tension variation that is

allowable and the magnitude of the expected tugs. The geometry of the pulley

assembly can also be adjusted to achieve the desired response.

For example, let us assume that the nominal tension of the fiber is 1.0 Newton,

the expected displacement demanded of the high frequency tugs is 1.0 mm, and the

maximum allowable variation in fiber tension is 0.1 Newton. In this case, a spring

would be chosen that deforms with 0.1 Newton of force enough to yield the 1.0 mm of

fiber required by the tug. For the geometry shown in Fig. 1 , assuming that the fiber

path turns 90 degrees at pulleys 32 and 36, the corresponding spring would have to have

a spring constant of 0.2 N/mm. Due to the nominal tension, this spring will also have

to also accommodate a compression of 10.0 mm during normal operation.

The assembly shown in Fig. 5 can be modified in a number of ways within the

spirit of the present invention. For example, as mentioned above, the spring 56 can be

replaced with a pneumatic piston, such as that shown in Fig. 7 and discussed below,

that contains a pocket of air and behaves like an elastic element. This particular

configuration has the advantage of less wear and tear, as there are no springs to wear

out. It would also be within the spirit of the present invention to add more pulleys

linked to springs, therefore distributing the tug load among more springs and reducing

the impact of one spring failure.

Fig. 6 illustrates a variation of the embodiment shown in Fig. 5. In the Fig. 6

system 42a, the regulator pulley 46a is located at the end of the pulley array, that is. closest to the takeup spool. This particular configuration offers a more immediate

response to the tugs, because there are no inertias between the tugging from the takeup

spool and the regulator pulley.

Fig. 7 shows a perspective view of a passive tension regulator pulley 58

according to the present invention. The pulley includes a disk 60 having a groove 62

around its circumference for receiving optical fiber. The disk 60 is rotatably mounted

into a yoke 64, such that the disk 60 freely rotates around an axle 66. The yoke 64 is

mounted to the piston shaft 68 of a pneumatic cylinder 70, which is fed by an air supply

line 72. The pneumatic cylinder 70 is mounted to the frame of the optical winder using

an L-shaped bracket 74.

As discussed above, the piston behaves like an elastic element to absorb high-

frequency tension fluctuations in the optical fiber being wound. The elasticity of the

piston shaft 68 is a function of the amount of air pressure provided by air supply line 72

to the pneumatic cylinder 70. In the present embodiment, the pressure of the air

contained within the pneumatic cylinder 70 is set to a predetermined level prior to

operation of the fiber winder and maintained at the level throughout the operation of the

winder.

Fig. 8 shows a diagram of an optical fiber winding system 76 according to the

present invention, for use in an off-line screening process. In Fig. 8, optical fiber 78 is

wound from a bulk spool 80 onto a shipping spool 82. The path for the fiber 78 is

defined by a series of eight pulleys 84-98. The array of pulleys includes two pulleys 86,

92, which are mounted to dancer arms and are linked to a controller which can control

the speed of the spindle in response to a change in dancer arm position. The winder 76

includes a takeup wing 100 on which are mounted the final three pulleys 94, 96, 98

leading to the shipping spool 82. Regulator pulley 96 is mounted to a pneumatic air cylinder 96, such as the one shown in Fig. 7. As described above, the regulator pulley

96 serves to eliminate high-frequency tugs on the optical fiber 78 as it is being wound

onto the shipping spool 82. The Fig. 8 system 76 also includes a load beam 104, which

is a tension-sensing device, i.e., a transducer, that provides fiber tension information to

controller 106. Controller 106 then displays the tension information to an operator,

thus providing a visual cross-check to help insure the proper functioning of the winding machine.

Fig. 9 shows a takeup wing 100a for use in an optical winding system according

to the prior art. In the prior art configuration, all three takeup pulleys 94a, 96a, 98a are

mounted to the takeup wing 100a using stiff supports. In addition, in the Fig. 9

configuration, load beam 104a is linked to pulley 96a. As mentioned above, load beam

104a is used to provide tension information to the controller 106a. This prior art

configuration suffers from the above-described high-frequency tugs on fiber being

wound onto the takeup spool, resulting in reduced wind quality.

Fig. 10 shows a takeup wing 100b for use in an optical winding system

according to the present invention. This configuration includes a regulator pulley 96b,

which is linked to the takeup wing 100b using a pneumatic cylinder 102b. In this

configuration, the load beam 104b is mounted proximate to dancer pulley 92b to

provide tension information to the controller 106b.

Fig. 11 shows a graph 108 comparing the tension experienced by the optical

fiber at the takeup spool using the takeup wings shown in Figs. 9 and 10. The lower

trace 1 10a shows the tension of the prior art system, and the upper trace 1 10b shows the

tension of the system according to the present invention. As is apparent, the system

according to the present invention shows a tension profile having markedly reduced

fluctuations. Fig. 12 shows a diagram of an alternative embodiment of the present invention,

incorporating an active feedback control loop. A controller 106c receives fiber tension

information from a load beam 104c. or other tension-sensing device. The controller

106c uses this information to increase or decrease the air pressure within the pneumatic

cylinder 102c, as needed, by making adjustments to the air supply 112. As discussed

above, the elasticity of the pneumatic cylinder 102c is a function of air pressure. In this

embodiment, the tension-sensing device provides an analog output to the controller

106c. The controller 106c is a PID (Proportional + Integral + Derivative) controller.

It will be apparent to those skilled in the art that various modifications and

variations can be made in the present invention without departing from the spirit and

scope of the present invention. Thus, it is intended that the present patent cover the

modifications and variations of this invention, provided that they come within the scope

of the appended claims and their equivalents.

Claims

What is claimed is:

1. An optical fiber winder, comprising:

a frame;

an array of pulleys for guiding fiber from a fiber source to a takeup spool, each

of the pulleys in the array being mechanically linked to the frame,

the array of pulleys including a regulator pulley linked to the frame by a passive

tension regulating element, the regulator pulley providing a fiber buffer for high

frequency tugs on the fiber being wound onto the takeup spool, the regulator pulley

further limiting tension oscillations in the fiber being wound onto the takeup spool.

2. The optical fiber winder of claim 1 , further comprising a second fiber

tension regulating element designed to regulate against tension variations in the fiber

which are of lower frequency or higher magnitude than said high frequency tugs.

3. The optical fiber winder of claim 2, further comprising a closed loop control

for adjusting either the tension applied by said second fiber tension

regulating element or the speed with which said fiber is being wound in

response to a change in tension in said fiber being wound.

4. The optical fiber winder of claim 1 , wherein the passive tension

regulating element comprises a spring.

5. The optical fiber winder of claim 3, wherein the passive tension

regulating element comprises a spring.

6. The optical fiber winder of claim 3, wherein the array of pulleys includes

first and second guide pulleys, and wherein the fiber is threaded in alternate directions

around the first guide pulley, the regulator pulley, and the second guide pulley.

7. The optical fiber winder of claim 3, wherein the array of pulleys includes

a guide pulley, and wherein the fiber is threaded in alternate directions around the guide pulley and the regulator pulley.

8. The optical fiber winder of claim 7, wherein the guide pulley is

proximate to the fiber source and the regulator pulley is proximate to the takeup spool.

9. The optical fiber winder of claim 3, wherein the passive tension regulating

element comprises a pressurized air pocket at the axle of the regulator

pulley.

10. The optical fiber winder of claim 9, wherein the pressurized air pocket is

created by an air jet.

11. The optical fiber winder of claim 1 further includes a tension-sensing

device for providing fiber tension information to a controller in a feedback control loop.

12. The optical fiber winder of claim 11 , wherein the regulator pulley is

linked to the frame by a pneumatic piston, the elasticity of which is a function of the air

pressure within the piston, and wherein the controller adjusts the elasticity of the piston

by increasing or decreasing the air pressure within the piston.

13. The optical fiber winder of claim 12, wherein the tension-sensing device

provides an analog signal as an output to the controller, and wherein the controller is a

PID controller.

14. A method for winding optical fiber, comprising the following steps:

(a) guiding fiber from a fiber source to a takeup spool using an array of

pulleys, each of the pulleys in the array being mechanically linked to a supporting

frame, one of the pulleys in the array being a first regulator pulley that is linked to the

frame by a first passive tension regulating element; and

(b) using the first regulator pulley as a fiber buffer for high frequency tugs

on the fiber being wound onto the takeup spool and limiting tension oscillations in the

fiber being wound onto the takeup spool.

15. The method of claim 14, further comprising guiding said fiber through a

second regulator pulley that is linked to the frame by a second tension regulating

element, said second tension regulating element regulating against lower frequency or

higher magnitude variations in fiber draw speed.

16. The method of claim 15, further comprising monitoring fiber tension or

fiber draw speed information and sending said information to a controller in a feedback

control loop to control either the tension on at least one of said first or second tension

regulating element, or the speed with which said fiber is being drawn.

17. The method of claim 14, wherein step (a) includes the following substep

(al):

(al ) using a spring to link the regulator pulley to the frame.

18. The method of claim 17, wherein substep (al) includes choosing the

spring according to the magnitude of allowable variation in fiber tension and the

magnitude of expected tugs on the fiber.

19. The method of claim 17, wherein step (a) includes the following substep

(al):

(al ) using a pressurized air pocket to link the regulator pulley to the frame.

20. The method of claim 17, wherein step (al) includes creating the

pressurized air pocket by an air jet.