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WO1996033430A1 - Ameliorations concernant le sectionnement de fibres optiques - Google Patents

Ameliorations concernant le sectionnement de fibres optiques Download PDF

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Publication number
WO1996033430A1
WO1996033430A1 PCT/GB1996/000919 GB9600919W WO9633430A1 WO 1996033430 A1 WO1996033430 A1 WO 1996033430A1 GB 9600919 W GB9600919 W GB 9600919W WO 9633430 A1 WO9633430 A1 WO 9633430A1
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WO
WIPO (PCT)
Prior art keywords
fiber
fibers
anvil
blade
range
Prior art date
Application number
PCT/GB1996/000919
Other languages
English (en)
Inventor
Ian John Murgatroyd
Original Assignee
Oxford Fiber Optic Tools Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GBGB9508035.4A external-priority patent/GB9508035D0/en
Priority claimed from GBGB9605587.6A external-priority patent/GB9605587D0/en
Application filed by Oxford Fiber Optic Tools Limited filed Critical Oxford Fiber Optic Tools Limited
Publication of WO1996033430A1 publication Critical patent/WO1996033430A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/25—Preparing the ends of light guides for coupling, e.g. cutting

Definitions

  • This invention relates to improvements in and relating to methods and devices for cleaving optical fiber materials, in particular, but not exclusively telecommunications fibers.
  • optical fiber materials usually glass
  • optical wave guide communication systems data processing and other signal transmission systems
  • terminal ends transmit light energy signals with minimum energy loss of signal when the end of the fiber is optically flat with a mirror smooth surface lying in a plane perpendicular to the longitudinal axis of the fiber filament.
  • Such a flat end allows easy and repeatable joining of the two adjacent fiber ends by a splicing technique in which the two fiber ends are fused or otherwise brought into close proximity to each other so that the optical signal suffers minimal loss of power in transiting the junction.
  • This method has advantages in that there is no need accurately to control the applied tension which serves to propagate the crack and that it can easily cleave several fibers, as might be found in a fiber ribbon, with one pass of the blade.
  • the method has certain drawbacks. Firstly, the blade tends to intrude into the fiber creating excess cracking of the fiber at the point of contact. Such cracks can be detrimental to the performance of the splice which is made up of two such cleaved ends. To achieve good cleaving performance, this necessarily implies that the blade must be aligned to the height of the fiber very accurately, typically to within + /-10 microns.
  • tension-and-score technique that it does not readily lend itself to cleaving multiple fibers at one time, as might be found in a ribbon fiber, because it is difficult to apply tension equally to all fibers at the same time. Instead there is a tendency to tension one or more fibers in the ribbon more than the others. Furthermore, the tensioning in each fiber must be independent from the tensioning in the neighbouring fibers in the ribbon. If the tensioning is not independent, after the first few fibers have been cleaved, the entire applied force will be applied to the remaining fibers, with the result that the remaining fibers support an ever larger tension. This leads to shattering of the ends of the final fibers to be cleaved.
  • an angled cleaved end may be desirable.
  • the back reflection from a cleaved fiber end must be reduced as far as possible, and this can be achieved by cleaving the fiber end at an angle; a 5° end angle on the fiber will reduce the back-reflection to less than -50dB.
  • both the score-and-break method and the tension-and-score method are unsatisfactory in that, whilst angles produced by the cleaving may be non- perpendicular, the end angle so produced is not controlled. Further, even when the prior art attempts to implement this technique the prior art method using "tension-and-score" techniques are difficult to use and are not well designed as hand tools.
  • the surfaces should be angled in a specific direction so that the reflection of specific polarisations of the optical signal can be eliminated.
  • the cleaving tool should be able to accept standard fiber holders, so that the optical fiber or fibers can be cleaved at a specific position, without the need to take it out of its holder.
  • a method of cleaving an optical fiber comprising the steps of restraining two spaced portions of the fiber, inducing and maintaining tension in the fiber between the two restrained portions, and scoring the tensioned fiber with an edge of a blade in order to create a crack in the fiber which initiates a cleave, the blade being moved relative to the fiber in a direction which makes an acute angle with the edge in the plane of the blade.
  • This method of cleaving an optical fiber has several significant advantages.
  • the use of an acutely angled blade means that whilst it contacts the fiber creating a crack which is propagated by the applied tension so cleaving the fiber, the movement of the blade radially into the fiber is demagnified by the angling of the blade and so leads to little bending of the fiber and so consistently low end angles.
  • the speed of cleave propagation is much higher than the penetration rate of the blade ensuring cleaving without the presence of extra cracking.
  • the blade can easily be aligned so that it will always contact a fiber which is held between the two clamps, tolerating some misalignment of the fiber within the clamps or variations in fiber size. Therefore, the cleaver according to this invention does not need accurate alignment, it is easy to manufacture, it will not go out of alignment during use and it will be serviceable in the field.
  • the method includes laterally displacing the fiber between the two restraining locations prior to scoring with the blade. Preferably this is done by the introduction of an anvil.
  • the bending of the fiber caused by the anvil is designed to resist and further minimise the opposite bending force of the blade as it bites into the fiber and so ensures that the fiber is always under tension at the point of the cut.
  • Most preferably the displacement directly opposes the blade to provide optimum support.
  • the lateral displacement preferably serves as a second mechanism to tension the fiber in addition to axial tensioning arising from an increase in the separation of the restraining locations. Control of the axial tension in the fiber allows control of the propagation of the cleave.
  • the total tension introduced into the fiber can be (as described with reference to Fig. 12) a superposition of pure tension arising from moving apart the two restraining locations and stress arising from stretching the fiber over the anvil.
  • the stress arising from stretching the fiber over the anvil is tensile on the outside bend of the fiber and zero on the inside bend of the fiber, i.e. the neutral axis lies at the edge of the fiber on the inside of the bend. (It should be noted that this is not the same as simply bending the fiber. Pure bending would give compression on the inside of the bend with a neutral axis half way across the fiber.
  • hackle is meant the characteristic surface irregularity which can be created by uncontrolled energy release in formation of the cleave. This ensures a mirror smooth surface. Any hackle arising from the cleave travelling too fast is confined to the extreme circumference of the cleaved end at 90 and 270 degrees to the point of cleaving; this will not affect the transmission of light through the fiber's core. The cleave will travel perpendicularly across the fiber because it always experiences positive tension.
  • the face of the anvil which acts to bend the fiber, is parallel with the edge of the acutely angled blade. Therefore, the fiber is trapped between the face of the anvil and the edge of the blade which is caused to score the fiber.
  • the anvil has two end portions separated by a recess.
  • the restraining locations comprise two pairs of opposing clamps, to provide firm restraint and ready release.
  • clamping surfaces at one or both of the restraining locations may comprise a V-groove into which the fiber is pressed by an opposing clamping surface. This has the effect of providing secure clamping of the fiber and decreases the possibility that the fiber will rotate during clamping, which would introduce torsion into the cleaved fiber.
  • clamps may be provided with a compliant surface. This allows cleaving of multiple optical fibers arranged in a linear ribbon fashion. Each fiber in the ribbon is gripped independently by virtue of the compliant surface. Each fiber in the ribbon is placed under a constant extension producing a constant axial tension therein and, consequently, each of the fibers in the ribbon will cleave in the same way with the same angle.
  • the compliant material can be made of a uniform material such as a hard rubber or plastic. However, after prolonged use, the material tends to become deformed as it is crushed by the pressure required to clamp the fibers, consequently shortening the lifetime of the clamping surfaces and leading to a deterioration of the cleaving performance.
  • compliant clamping pads can be made of a matrix structure such as a fiber matting, made up of kevlar, carbon or glass fibers, held together by a bonding agent such as epoxy.
  • a bonding agent such as epoxy.
  • the hard fibers in the surface made of kevlar for example, resist the crushing pressures so that the clamping surfaces is not permanently marked.
  • the softer bonding material of the clamping surface yields under the clamping force. This ensures that all of the glass fibers in the ribbon are clamped by the compliant pads, even if there is a slight variation in the diameters of the glass fibers in the ribbon.
  • the fibers in the compliant surface are typically 10 microns in diameter, so the glass fiber is clamped by several of them simultaneously, spreading the crushing load.
  • the fibers in the compliant pad are preferably arranged in one direction, parallel to the glass fiber which is to be clamped, so reducing the danger of breaking it.
  • the most successful material fiber material in the compliant pad is comprised of a hard, yet tough, fiber such as Kevlar.
  • the compliance of the compliant surface can be modified by changing the stiffness of the bonding material, where this material could be epoxy resin, polyester, polyethylene, polyetheretherketone (PEEK) , polyphenylenesulphide (PPS), carbon or some other elastic material.
  • each of the restraining means at the restraining locations are free to move relative to the other so as to permit the separation of the restraining locations to be increased and tension introduced. This simplifies construction and allows the restraining means and tensioning means to be one and the same.
  • one or both of the clamps comprises a deformable member. It is preferred that the contacting location between the member and the fiber, at the restraining location, should move further from the other restraining location as the member is deformed. Clamping is thus adequately effected with further compression causing tension to be introduced into the fibers.
  • a spring forms the clamp and preferably the other clamp is a movable surface, most preferably a pivotally movable surface such as a roller or a second spring. It is particularly advantageous to provide one clamp of each of the pairs by means of a single common spring or to provide both clamps of each of the pairs by means of two opposing springs.
  • a second anvil may also be introduced, most preferably opposing the first anvil. This also allows the cleaving of controlled angled ends onto single or multiple optical fibers by cutting the fiber at a point where shear stress of a controlled level is present in the fiber.
  • the fiber is tensioned and the first anvil creates a lateral displacement to resist the cutting of the blade as above, and the secondary anvil is introduced, approximately in opposition to the first anvil, to increase the bending of the fiber to create shear forces which will lead to an angled cleaved end.
  • This embodiment of the invention has the advantage that the same tool can be used either to cleave angled ends onto a fiber or fibers, by the simple means of introducing the secondary anvil, using an actuating device such as a lever, or to cleave perpendicular ends onto a fiber or fibers by not applying the secondary anvil.
  • a further method of cleaving angled ends is optionally provided by introducing a secondary anvil which is moved to displace the fibers laterally in a direction perpendicular to the action of the first anvil. Consequently, the fibers are subject to a shear stress which will lead to angled ends when cleaved.
  • This displacement is preferably achieved by contacting the fibers with the secondary anvil, which is preferably tipped with a compliant material, and moving it with a component of sideways motion with respect to the first anvil, for example by rotating it around a pivot or sliding it.
  • the cleaved angles so produced will be arranged in an approximately perpendicular orientation with respect to the angles produced by the previous method. Therefore the two methods will be effective in decreasing back reflections for opposing optical polarisations. Any rotation of the fibers as they are being displaced will give rise to torsional stresses in the fiber which will also give angled ends when cleaved.
  • cleaved ends may be produced with angles of between 1 and 15 degrees, and preferably between 4 and 10 degrees, titled in the desired orientation, whilst still producing planar surfaces with minimum damage caused by cleaving.
  • the angle of the plane of cleavage can optionally be controlled or varied according to the level of shear force introduced. This can in turn be controlled by the extent of displacement generated by the secondary anvil.
  • the level of shear can also be controlled according to the following optional and alternative methods.
  • An alternative method of cleaving angled ends is optionally provided by rotating the two-portioned anvil about an axis perpendicular to the fiber, either before or after contact, so that the bending of the fiber is non-symmetric, i.e. it is twisted. This maybe done by a simple actuating method whereby a perpendicular setting for the anvil produces perpendicular ends whereas a rotated or part rotated anvil produces angled cleaves.
  • the ends of the two-portioned anvil should be tipped with a compliant material so that they contact the fiber over a significant fraction of its diameter to insure that, between the two arms of the anvil, a twist is applied to the fiber; the use of a hard tip to the anvil leads to point contact between the fiber and the anvil and so no twisting force will be applied to the fiber.
  • an one-armed anvil to achieve angled cleaves rather than a two-armed anvil to produce perpendicular cleaves can easily be achieved by means, for instance a lever, to change the form of the anvil by withdrawing one of the portions so leaving the fiber unevenly displaced.
  • twisting of one or both pairs of clamps relative to the other, for instance about the axis of the fiber, can be used to create non-axial stress in the clamped and tensioned fiber or fibers.
  • angled cleaving can be achieved by providing a two portion anvil and introducing the step of rotating one portion relative to the other such that the support provided by the arms is not parallel, where both portions of the anvil are tipped with compliant material.
  • Such a tool is preferably manually operable with manual pressure being used to cause the clamping, tensing, optional lateral displacement and scoring leading to cleaving the various stages occurring in progression as the device is progressively compressed.
  • the device is designed to be lightweight and portable, whilst being sufficiently rugged for use in the field. However, the same is easily adapted for bench-mount operation.
  • Means can also are provided in the tool for regulating the location of the fiber cleavage so as to select the length of fiber remaining between the point of cleavage and the end of the stripped coating selected in accordance with the requirements of the particular application required.
  • Means can also be provided to cleave an optical fiber or fibers held in various connector devices with either a perpendicular or angled end with a specific distance between the end of the connector device and the cleaved fiber or fibers.
  • a device for use in cleaving optical fibers comprising restraining means whereby two spaced portions of a fiber can be secured, tensioning means whereby tension can be induced and maintained in the fiber between the two spaced portions, and means adapted to hold a scoring blade in engagement with the fiber and to move the blade relative to the fiber in order to create a crack in the tensioned fiber which initiates a cleave, the blade-holding means being arranged to move the blade in a direction which in the plane of the blade made an acute angle with the edge of the blade.
  • the use of a blade angled acutely to its direction of motion to score the fiber has several advantages.
  • the frictional force between the blade and the glass is substantially less for a near tangential blade motion than for a perpendicular blade motion and it is only required to exert a small force to score the fiber which is therefore not substantially displaced by the blade.
  • due to the acute angling of the blade its radial motion relative to the fiber is substantially demagnified compared to the speed of the blade's lateral motion relative to the fiber. Consequently the sharp blade contacts the tensioned fiber gently, minimising the lateral forces which cause bending of the fiber.
  • the motion of the blade relative to the fiber is self-limiting.
  • the restraining locations are separated by a distance in the range 0.25mm to 100.00mm, or even more preferably in the range of 0.25mm to 30.0mm.
  • the optical fiber does not bend significantly under the influence of the blade during scoring and so the fiber remains under tension at the point of incision such that the crack is propagated as a cleave.
  • the angle between the edge of the blade and its direction of travel during scoring may be between 0.5 and 45 degrees, and most preferably in the range 2 to 45 degrees, where 90 degrees equates to a blade moving perpendicular to its edge.
  • the linear section of the fiber is preferably placed under an axial tension by increasing the spacing of the two restraining locations.
  • the restraining means and consequently the restraining locations may be defined by pairs of opposing clamps of various forms. Bringing the clamps together may thus serve to hold the fiber whilst their release allows the cleaved fibers to be withdrawn.
  • Means may be provided to limit the approach of the clamps to one another so as to prevent overclamping of the fiber.
  • One or both of the clamp surfaces maybe made of a hard material such as hardened steel.
  • One or both of the clamp surfaces of one or both of the holding locations may incorporate a V-groove into which the fiber is pressed during clamping to ensure that the fiber is securely clamped without rotation.
  • one clamp of each pair is part of a common deformable member. Most preferably this is a spring.
  • the other part of each clamp is in the form of a roller. The roller is preferably shaped such that it is substantially flat but which can rotate independently around an axis to allow the longitudinal extension of the fiber.
  • the other part of each clamp is also in the form of a common deformable member. Most preferably, this is also a spring.
  • the common member or members Preferably compression of the common member or members cause the restraining locations formed thereby to move apart so generating tension in the fiber.
  • the provision of the other clamp as rollers or as a second common member aids in accommodating this movement.
  • the clamping surfaces of either or both of the deformable members and/or the rollers are angled inwards prior to clamping, as shown in Fig. 13. As the fiber is clamped and stretched, the clamping surfaces bend or rotate towards the horizontal, as shown by arrows Yl , Y2, Y3, Y4, ensuring that the clamped fiber is always urged outwards, hence tensioning it.
  • the restraining means and tensioning means are preferably one and the same.
  • the device is also provided with means to laterally displace the fiber between the two restraining locations prior to cleaving.
  • This lateral displacement serves to stretch the fiber between its two restraining locations imparting a tension to the fiber in addition to that arising from moving apart the two restraining locations.
  • the lateral displacement bends the fiber, increasing the tension on the outside of the bend and decreasing it on the inside of the bend. Bending the fiber in this way is designed to resist and further minimise the opposite bending force of the blade as it contacts the fiber. In this way the device ensures that the fiber is always under tension at the point of incision of the blade whatever the distance between the restraining locations
  • the extent of displacement may be adjustable to allow for optimum displacement for different fiber diameters and materials.
  • Stop means may be provided to limit the extent of displacement as desired.
  • the clamped fiber is extended by approximately 2 parts in 1 ,000 of the distance between the two restraining locations.
  • the anvil be split into two portions with a recess between them.
  • the bending force is applied at two points so the fiber experiences a four-point bending condition (with the clamps making up the remaining two locations) , which gives a substantially zero shear stress in the fiber in the region between the two parts of the anvil.
  • the cleave is preferably initiated. Consequently, the cleave so produced will be perpendicular, as is required in the technology of joining optical fibers.
  • the face of the two portions of the anvil will be in the same plane as the edge of the acutely angled blade so that the fiber will be trapped therebetween and so scored by the edge of the blade.
  • anvil may pass through the spring and so into contact with the fiber.
  • the sharp blade maybe made of a hard, tough material such as diamond or Zirconia.
  • the blade may be adjustable so as to allow different portions of the blade to be presented to the fibers during its working life as the blade wears or gets damaged.
  • each pair of clamps is provided with a compliant surface.
  • the multiple fibers in the ribbon can thus be clamped between the two restraining locations, both of which have some degree of compliance on one or both of their faces so that they can grip each fiber in the ribbon independently. Because each fiber is placed under a constant extension, as each fiber in the ribbon is progressively cleaved, the tension in the remaining fibers is largely unaffected, hence all of the fibers are cleaved under approximately equivalent conditions.
  • the compliant pads preferably have a surface which comprises a fiber-matrix composite.
  • the matrix is made of epoxy or a similar material to provide compliance.
  • the fibers are made of Kevlar, or similar, to provide hardness and toughness to stop the compliant pad crushing and being damaged under the clamping loads.
  • the Kevlar fibers are preferably laid unidirectionally, parallel to the glass fiber to prevent its breakage during clamping.
  • the apparatus also includes a secondary anvil which maybe introduced so as to displace the fiber in a controlled manner.
  • a secondary anvil which maybe introduced so as to displace the fiber in a controlled manner.
  • this invention also allows for controllable end angles to be cleaved onto single or multiple fiber ribbons.
  • the cleave in a fiber will propagate in a direction perpendicular to the resultant applied tension in the fiber thus a shear or torsional stress must be induced in the fiber such that when this stress is combined with the applied tension, the maximum stress lies at an angle to the axis of the fiber.
  • This the secondary anvil does.
  • the secondary anvil is provided in opposition to the first and ideally it abuts the fiber between the two arms of the two part anvil.
  • a secondary anvil applied in this way is used to increase the bending forces acting on the fiber in the region of the cleave.
  • the secondary anvil acts with a controlled force on the fiber or fibers, in opposition to the original anvil at a point close to or in between the arms of the first anvil such that the fiber or fibers are significantly bent so creating shear forces.
  • the secondary anvil is preferably tipped with a compliant material which is deformed on contact with the fiber or fibers so exerting a shear force on them.
  • the bent fiber or fibers are then scratched with the blade at a point on the outside of the bent fiber preferably within a few fiber diameters of the point of action of the secondary anvil and this will lead to a cleave which is angled.
  • Cleaving of the fibers is achieved by scratching each fiber in the ribbon with an acutely angled blade so that they cleave substantially simultaneously with the same cleave length. Subsequently, each fiber in the ribbon is bent equally across the anvil. Consequently, each fiber is equally tensioned and bent, but the stresses are independent, and if one or more fibers in the ribbon are cleaved, the stresses in the other fibers will not be altered. Finally cleaving is initiated by scratching each fiber with an angled blade, where the blade edge is parallel with the plane of the fiber ribbon and also parallel with the end of the two part anvil so that each fiber is scratched and hence cleaves substantially simultaneously.
  • the position of the secondary anvil and the blade, and the force with which the secondary anvil bends the fiber or fibers, are preferably controlled to produce a cleave end angle in the range of 1° to 15° and preferably an angle of 4°-10°.
  • This method is also effective in cleaving end angles onto a multiple fiber ribbon, where the secondary anvil is tipped with a compliant material so that it can exert equal bending forces and so produce equal stresses in, and hence cleave end angles on, each fiber in the ribbon.
  • the direction of motion of the secondary anvil can be controlled so that it laterally displaces the fibers with components both in opposition to and perpendicular to the direction of the first anvil. This will serve to control the orientation of the shear created in the fibers and hence the orientation of the cleaved end angles.
  • a secondary anvil which is moved in a direction with a component of motion such that the fibers are displaced perpendicular to the direction of motion of the first anvil, shearing the fiber, but where the direction of motion of the second anvil also has a component of movement acting in opposition to the first anvil so that the fibers are properly gripped by the secondary anvil.
  • the secondary anvil is tipped with a compliant material so that the fibers are gripped.
  • the secondary anvil is applied after the fibers have been displaced by the first anvil.
  • the sideways motion of the secondary anvil will also lead to a rolling of the fibers which will induce a torsional force in the fiber which will also lead to angled ends.
  • the first anvil will also be tipped with a compliant material to allow the fibers to be gripped when subjected to this rolling force.
  • the extent of movement of the secondary anvil giving rise to lateral displacement and/or rolling of the fiber may be adjustable to allow for optimal cleaved end angles oriented in optimal orientations.
  • the device may be provided with means to rotate the anvil about an axis perpendicular to itself and so perpendicular to the axis of the fibers to be cleaved.
  • the bending will not be symmetrical, and so shear forces will be created in the fiber, leading to an angled cleave.
  • the end of the first anvil is tipped with a compliant material to ensure contact between the anvil and the fiber, over a significant fraction of the fiber's circumference, so that the fiber experiences the shear force arising from the rotated anvil.
  • the device is provided with an anvil having a single arm or two non-symmetrical arms, which result in shear forces when bending and when the fiber or fibers are scored cause the cleaved end or ends to be angled.
  • the ends of both parts of the anvil are tipped with a compliant material to ensure contact, over a significant fraction of the fiber's circumference, between the anvil and the fiber.
  • the device can be provided with a two part anvil, the two parts being rotatable relative to one another.
  • the arms can be arranged parallel to one another and so lead to a straight cleave, alternatively the arms can be rotated relative to one another and so given uneven support leading to an angled cleave.
  • the extent of rotation is used to control the angle of cleave.
  • the device can be provided with means to rotate either or both of the restraining means about the axis of the fiber following clamping so as to introduce a torsional force.
  • the cleaved angle achieved depends upon the relative values of torsion and tension in the fiber. Specifically, for a fiber tension of 200 grams, to achieve an end angle of 5°, the holding sections must be twisted relative to each other by an amount of approximately 5° per centimetre between two points of clamping.
  • This method also allows end angles to be cleaved onto multiple fiber ribbons held in compliant clamps. Torsion is applied to each of the tensioned fibers at the same time by rotating both of the holding sections in opposite directions.
  • the fibers are substantially in a line at the midpoint between the two clamps and so they can be cut by the acutely angled blade. All of the fibers in the ribbon will experience the same tension and torsion and so they will cleave with similar end angles.
  • the tool will be provided with channels into which the fiber or fibers can be Iain to constrain them laterally during cleaving.
  • One of these channels will be of slightly larger width than 125microns diameter of the glass fiber.
  • a second co-linear channel will be of width slightly larger than the coating diameter of 250microns or 900microns. This second channel may have two sections of widths corresponding to a choice of coating diameters.
  • the ends of the channels will act as stops for the stripped fiber giving predetermined cleave lengths, as might be required by specific cleaving applications. To allow the user to chose other cleave lengths, a scale will be included.
  • the second channel in the cleaving tool will also included a deformable rubber side or rubber insert which will temporarily trap the fiber coating in the channels prior to cleaving to ensure that the fiber coating does not move during cleaving.
  • the tool will preferably have a removable ledge on which the length of coated fiber, and any associated cabling, can be rested and held during cleaving.
  • the cleaving tool will also have a fitting so that a standard holder, containing the fiber to be cleaved, can be clipped onto the tool, without the need to remove the fiber from its holder. This will give a standard cleaved fiber length, as is required by certain applications.
  • the invention provides a device for use in cleaving optical fibers comprising restraining means whereby two spaced portions of a fiber can be secured, first tensioning means whereby tension can be induced and maintained in the fiber by urging the two restraining portions apart, second tensioning means whereby tension can be induced and maintained in the fiber by laterally displacing the fiber between the two restrained portions, and means adapted to hold a scoring blade in engagement with the fiber and to move the blade relative to the fiber in order to create a crack in the tensioned fiber which initiates a cleave, the first and second tensioning means being independently adjustable to determine the stresses in the fiber prior to engagement of the fiber by the blade.
  • Figures 1 and 2 are illustrations of tools which are used in prior art to perform cleaving, manufactured by York Technology Ltd, UK and RXS GmbH, Germany, respectively;
  • Figure 3 shows schematically an acutely angled blade scoring an optical fiber
  • Figure 4 shows the experimental jig used to demonstrate the cleaving principles of this invention
  • Figure 5a shows an end-on view of one embodiment of the cleaving tool
  • Figure 5b shows an side-on view of the open cleaving tool of Figure 5a
  • Figure 6 shows the optical fiber bent by the two-armed anvil
  • Figure 7a shows an optical fiber bent by both the two arms of the first anvil and the secondary anvil, hence introducing shear stresses in the optical fiber to obtain angled cleaving;
  • Figure 7b shows a side-view of the action of the secondary anvil in the cleaving tool
  • Figure 7c shows an end-view of the lower working head of the cleaving tool showing the action of the secondary anvil
  • Figures 8a and 8b show a method to obtain angled cleaving, in side-view and bottom-view, where an optical fiber is bent by a two- armed anvil, where the anvil is, respectively, perpendicular to the fiber giving perpendicular cleaves, or rotated with respect to the fiber giving angled cleaves;
  • Figures 9a and 9b respectively show a method to obtain angled cleaving where use of an anvil with two arms gives rise to a perpendicular cleave, whereas use of an anvil with one arm gives rise to an angled cleave;
  • Figures 10a and 10b show a modified device for achieving angled cleaves in which parts of the anvil can be rotated relative to one another;
  • Figure 11 shows a method to obtain angled cleaving where the fibers may be twisted prior to cleaving to give angled cleaves or not twisted to give perpendicular cleaves;
  • Figure 12 shows the resultant tension present in a fiber 1 , as a superposition of the tensions arising from extending the fiber, by moving apart the clamping means, and stretching the fiber over the anvil 9 which has been advanced a distance h, where the broken lines indicate the position of the fiber l 1 and anvil 9' before bending;
  • Figure 13 shows the clamping (bending by the anvil 9) of the fiber 1 arising from preferably both surfaces of the upper and lower clamping means being initially angled inwards such that further clamping force will rotate these clamping surfaces outwards, hence further tensioning the fiber;
  • Figure 14 shows multiple fibers in a ribbon clamped between an upper, hard clamp and a lower, compliant pad made up of a composite of fibers and matrix.
  • Cleaving or fracturing of brittle objects such as optical fibers depends upon control of the stresses present within the optical fiber.
  • One method of stressing a glass fiber is to place it under tension, as shown in Fig. 1 , for example the cleaving tool manufactured by York Technology Limited.
  • An optical fiber 1 is clamped in two clamps 56a, 56b, 57a, 57b and placed under tension of around 200grams (for a 125micron diameter glass fiber) using a spring 58.
  • a sharp chopping blade 6, which is vibrating as shown by arrow A will score the fiber and lead to a good quality cleave.
  • An alternative method of stressing an optical fiber known from cleaving tools manufactured by Sumitomo, Japan and by RXS, Germany, is to bend the fiber, and consequently, the outside of the fiber will be under tension which can be used to start a fracture. Pure bending creates compressive stresses on the inside of the bend which gives rise to bad cleaved end faces. Therefore the fiber is stretched over an anvil, applying both bending and tension. Fig.
  • FIG. 2 shows the RXS tool in which the optical fiber 1 is clamped in two clamps 59a, 59b, 60a, 60b, with one face of each clamp sprung with springs 61a, 61b so that the fiber is first clamped and then stretched over an anvil 62; further closure of the tool brings the outside of the bend of the stretched and tensioned fiber 1 into contact with a sharp blade 6 which damages the fiber, creating an initiation crack, which is propagated by the applied bending and tension forces, causing the fiber to cleave.
  • the fiber is preferably both tensioned and bent, and so it will experience a stress profile which is the superposition of the tension and bending forces. Therefore, the tensile stress in the fiber will be highest on the outside of the bend where the tension and bending forces are additive, will be less in the centre where the stress is solely due to the tension and will decrease further on the inside of the bend where the tensile force and the bending forces subtract.
  • the applied fiber tension must be limited to about 200 grams to obtain a mirror-smooth cleaved surface, otherwise hackle begins to occur on the final part of the surface to cleave because the tension is too high.
  • the propagating cleave will experience a decreasing applied tensile force as it crosses the fiber, and this will reduce the tendency for the cleaved surface to exhibit hackle. Consequently, compared to prior art technologies where only either tension or bending is used to stress the fiber, a higher cleaving tension can be used without the appearance of hackle, giving the advantage of smaller starter cracks and flatter cleaved end faces.
  • the present method can achieve a very low end angle cleave by substantially eliminating both shear stresses and torsional stresses on the fiber during the cleave in several ways.
  • the crack is initiated by scoring the fiber 1 with an angled blade 6, the blade edge being acutely angled at an angle ⁇ with respect to its direction of motion towards the fiber, arrow I, as shown in Fig. 3.
  • the use of an acutely angled blade in this invention reduces the force required to score the fiber and so improves the consistency of the cleaves produced.
  • Previous technology uses a chisel or chopping motion to create the starter crack, where the blade moves perpendicular to the fiber.
  • the present method minimises shear and torsional stresses by stretching and subsequently bending the fiber over an anvil which is split into two arms and so provides a four-point bend configuration to the fiber. Consequently shear stresses are substantially eliminated in the fiber at all points between the two parts of the anvil.
  • torsion of the fiber is substantially eliminated by prevention of both sideways movements and any rocking motion of the clamps when the fiber is clamped.
  • the present method can also cleave multiple glass fibers arranged in a ribbon form.
  • the compliance can be achieved by using a clamping surface which is a fiber/matrix composite, in which the compliance is controlled by the properties of the matrix material, such as an epoxy, whereas the crush resistance is determined by the presence of hard, tough fibers, such as Kevlar, in the composite which resist the crushing forces of clamping onto the glass fiber.
  • Current technologies achieve a compliant clamping surface by using a rubber-like surface which is easily damaged by the clamping forces, and consequently has a limited operational life.
  • angled ends can be created on the glass fibers. Firstly, this can be achieved by either rotating the anvil so that the fibers or by rotating the two parts of the anvil in opposite directions, where the end of the anvil is tipped with a compliant material. Both of these methods give non-symmetric stresses in the fibers and lead to angled cleaving. Current devices, using a rotation of the anvil, are only able to cleave angled ends onto a single fiber.
  • the secondary anvil can be moved in opposition to the first anvil to bend the fibers, introducing shear forces which will give angled ends on cleaving.
  • the secondary anvil can be moved to bend the fibers in a direction perpendicular to the first anvil, giving shear stresses and angled cleaved ends.
  • the secondary anvil can also be used to roll the fibers, hence giving rise to torsion and angled cleaved ends.
  • the controlled action of the secondary anvil simplifies the production of angled ends.
  • the direction of motion of the secondary anvil allows the orientation of the angled cleaved end to be altered. Current angled cleaving devices are not able to alter the orientation of the angled ends.
  • Optical fibers were cleaved using an experimental jig as described below. Standard telecommunications fiber was used, comprising
  • 125micron diameter single mode silica fiber where its acrylate buffer had been stripped off to a length of about 30 millimetres to allow each cleave to be carried out.
  • An experimental jig was constructed as shown in Fig. 4, whereby the stripped optical fiber 1 was clamped between two holding sections 63a, 63b and one holding section 63b was urged away from the other by the application of a force originating from a weight W via a pulley system.
  • the holding sections 63a, 63b were restrained from moving apart because of the optical fiber 1 held therebetween, consequently inducing a tension in the optical fiber.
  • the optical fiber was passed over a two-armed anvil 64, such that the fiber was bent upwards by a controlled amount h, where h could be varied by changing the height of the anvil 64 relative to the plane X of the optic fiber. In this way the optical fiber was both tensioned and bent. Scoring of the optical fiber 1 was then achieved using a diamond blade 6.
  • the blade used was a 1.6mm long polished diamond blade incorporating a 60° included angle, obtained from Drukker International, Holland.
  • the blade 6 was mounted in a Vickers hardness indenter which provided a damped motion of the blade 6 travelling towards the fiber 1 , such that the blade contacted the tensioned and bent fiber at a point between the two arms 65a, 65b of the anvil 64.
  • the blade 6 was mounted so that its edge moved at an acute angle towards the fiber 1 and its direction of motion was adjusted so that the edge of the blade was always parallel to the surface of the anvil.
  • the cleaves produced were observed in an optical microscope at 200x magnification with the cleaved fiber end mounted vertically in a V- groove inscribed on the side of a steel block and constrained with a flexible magnet.
  • the end angles obtained were assessed using a 20x interference microscope objective (obtainable from Nikon, UK) , operating in green light, which gave 8 interference fringes for a cleaved 125micron fiber end with a 1° end angle..
  • the separation of the holding section was also investigated.
  • a clamp separation d of 12mm the best cleaves were obtained for an anvil displacement h of around 200-250microns. Smaller anvil displacements gave poor cleaves with large initiation cracks whereas larger displacements gave cleaves with circular features indicative of microsteps on the cleaved surface.
  • the optimum fiber tensions were again found to be around 200grams.
  • the end angles of the cleaves produced were investigated by using a microscope to view the cleaved ends which were held vertically under an interference lens, where the separation d of the holding sections was 12mm, the tension applied was 200grams and the displacement of the tensioned fiber by the anvil was 200microns.
  • the end angles achieved from the cleaves were all in the range of 0.25° to 0.75°.
  • the experimental jig was also modified to be used to study and evaluate the generation of cleave end angles onto an optical fiber.
  • a secondary anvil 66 was introduced to provide a controlled bending force on the fiber at a point between the arms 65a, 65b of and in opposition to the first anvil 64.
  • a clamped fiber 1 tensioned to 200 grams was initially displaced by the first anvil by a distance h of around 400microns, as described above, where the clamp separation d was 18mm and the anvil was centrally located between the clamps 63a, 63b, with a distance between the centre of its two arms 65a, 65b of approximately 2.5mm.
  • a secondary anvil 66 consisting of a narrow edge 67 pressed down upon by a known weight 68, was used to apply a controlled bending force to the fiber in opposition to the bending force applied by the first anvil 64, acting downwards at a point on the fiber approximately equidistant between the two arms 65a, 65b of the first anvil.
  • the diamond blade 6 was scored against the fiber at a point very close to the secondary anvil and between the points of contact between the fiber and the two arms of the first anvil 65a, 65b.
  • the arrangement of the primary and secondary anvils are shown in Fig. 4.
  • a weight 68 of 27grams was applied to the secondary anvil 66 and a number of cleaves were obtained with an average end angle of approximately 6.4°, whilst a number of cleaves carried out with weights of 20grams and 12grams gave average end angles of approximately 3.9° and 2.5°, respectively.
  • the end angles were consistent to approximately + /-1°. It would be expected that accurate control of the positioning of the secondary anvil and of the position of its contact with the fiber would decrease the variation in end angle achieved for a given force applied. Furthermore, the end angle achieved would be expected to increase for an increase in the bending force applied by the secondary anvil.
  • Fig. 5a shows an end-on view
  • Fig. 5b a side-on view of the tool which embodies this invention.
  • a length of optical fiber 1 which has been stripped of its coating 2 is placed in the tool.
  • the tool consists of a bottom block 3 and a middle plate 4, which are brought together by rotation around a hinge 5 by an operator in use, hence clamping, tensioning and bending the optical fiber 1.
  • the middle plate 4 acts as a solid mount for a steel clamp spring 7 whose bottom surfaces 8a, 8b serve to clamp the optical fiber 1 when the tool is closed.
  • the clamp spring 7 contains a central hole through which passes an anvil 9 and an anvil bush 10. As the clamp spring 7 is compressed, it extends laterally and therefore stretches the clamped optical fiber 1, so placing it under tension, as required for effective cleaving. Subsequently, the anvil 9 comes into contact with, and serves to bend, the clamped and tensioned optical fiber 1 towards the bottom block 3.
  • the clamp spring 7 is secured to the middle plate 4 by being clamped between a tilting plate 11 and a securing fastener 12.
  • the orientation of the clamp spring 7 can be adjusted by tilting the plate 11 using one of the adjustment screws 13a, 13b in order to ensure that the clamp spring 7 clamps the fiber 1 simultaneously with both of its legs.
  • the bottom block 3 contains two hardened, ground and polished steel roller blocks 14a, 14b whose upper surfaces 15a, 15b serve to clamp the optical fiber 1.
  • the roller blocks 14a, lb are free to rotate around their ground edges 16a, 16b which are pressed into a location plate 17 which has matching grooves 18a, 18b.
  • the tool is operated by pressing down on the handle plate 19a which rotates around a hinge 19b and compresses the handle spring 20a, 20b, 20c, where the two outside fingers of the handle spring 20a, 20b exert a downwards force on the middle plate 4. This compresses the tool opening spring 21 which allows the middle plate to move downwards, trapping and clamping the optical fiber 1 between the bottom surfaces 8a, 8b of the clamping spring 7 and the top surfaces 15a, 15b of the rollers 14a, 14b.
  • the handle spring 20a, 20b exerts a greater downward force, causing the clamping spring 7 to extend laterally, stretching and hence tensioning the clamped fiber 1 ; the rollers 14a, 14b rotate about their ground edges 16a, 16b to accommodate this movement.
  • the extension of the fiber brought about is approximately 2 parts in 1000, and this is equivalent to applying the 200gramforce of tension found to be optimal for cleaving in the experiments described above.
  • the centre part of the handle spring 20c forces the anvil 9 downwards to contact the clamped and tensioned fiber 1.
  • the anvil 9 is prevented from moving too far and applying more than the required deflection of the optical fiber 1 by its attachment to an anvil plate 22 and an adjustment screw 23 which comes into contact with the top surface of the anvil bush 10.
  • An anvil return spring 24 is also provided.
  • the end of the anvil 9 is slotted, being comprised of two arms, 25a, 25b, which contact the optical fiber 1 at two points and therefore place it under a four-point-bend condition and consequently reduce the effect of any torsion or shear forces in the optical fiber 1 , as sketched in side-view in Fig. 6.
  • the diamond blade 6 is mounted in a bracket 26a which is pivoted around a pin 27a, 27b; the bracket has an extension 26b and a return spring 26c.
  • the shaft of the pin 27a acts as the pivot on which the bracket 26a is mounted and around which the bracket 26a, and hence the blade 6, rotates.
  • the pin also has a shoulder 27b which is slightly eccentric to the shaft of the pin; this eccentric shoulder 27b is used to mount the pin in a pivot holding block 28. Rotating the pin around its shoulder 27b will raise or lower its shaft 27a and hence the bracket 26a and the blade 6, relative to the pivot holding block 28. This has the effect of setting the height of the blade 6, ensuring that the blade 6 will make contact with and score the fiber 1 to the desired extent.
  • the angular position of the pivot pin 27, and hence its height, is fixed by a locking screw, 29.
  • the bracket has an extension 26b, on the end of which is attached an adjustment screw 30.
  • a vertical rod 31 is passed through a bush 32 such that it is free to slide vertically in the bottom block 3 but its downward movement is limited by its head coming to a stop against the top surface of the bush 32.
  • a spring 33a is provided to urge the rod 31 upwards and a collar 33b is present to restrain the rod 31 in the bush 32.
  • the handle plate 19a and the handle spring 20a, 20b, 20c are released.
  • the springs 24 and 21 will, respectively, raise the anvil 9 and the middle plate 4, opening the tool and allowing the cleaved fiber 1 to be removed.
  • the pivot holding block 28 In addition to the height setting obtained from the eccentric shoulder on the pivot pin 27b, the pivot holding block 28, the pivot pin 27a, b, the bracket 26a, b and hence the blade 6, can also be translated in order to move a new part of the blade 6 into contact with the optical fiber 1 during cleaving, as will be required as the blade becomes blunt or chips during use. This has the effect of using several positions on the blade 6 for scoring the fiber, significantly extending the tool's life.
  • the pivot block 28, in which is mounted the pivot 27a, b, the bracket 26a, b and hence the blade 6, is threaded to accept a screw 36.
  • the screw 36a has a shoulder on its end so that it can be positioned in the bottom block 3 such that it is able to rotate; it is securely held by a fastener 36b. When the screw 36a is rotated it will translate the pivot block 28 parallel to the edge of the blade 6 to bring a new part of into use.
  • a modified version of the tool can also cleave multiple fibers arranged in a ribbon, where a ribbon may be made up of between 1 and
  • a compliant material such as a fiber-matrix composite.
  • a compliant material such as a fiber-matrix composite.
  • Kevlar, and filler matrix material 73 such as epoxy.
  • Each fiber in the ribbon is tensioned by a combination of the fiber extension arising from the extension of the clamp spring 7 with which each fiber in the ribbon is clamped and the displacement of the each fiber by the anvil 9.
  • the tension arising from the displacement of the fibers by the anvil is substantially greater than that arising from the extension of the clamp spring 7. Because the tension in each fiber due to its displacement by the anvil is independent of any other fibers in the ribbon, as each fiber in the ribbon is cleaved, the tension in the remaining fibers is not significantly increased and so they are cleaved in their turn under substantially equal tensioning conditions.
  • the blade 6 is rotated around its pivot 27a so that its edge contacts all of the fibers in the ribbon at substantially the same time, scratching all of them and causing each of them to cleave.
  • the length of the blade must be increased so that all of the fibers can be contacted at the same time; a 12 fiber ribbon will require a blade which is approximately 3mm long or greater and may be made from diamond, a tough ceramic such as Zirconia or some similar hard and tough material.
  • the tool here described in its single or multiple fiber form by suitable design, is able to cleave angled ends onto optical fiber or fibers 1 , with end angles in the range of 1° to 15° and preferably in the range of 4° to 10°. This is achieved by incorporating shear stresses into the fiber.
  • a single fiber in the single fiber tool As the middle plate 4 is lowered, the optical fiber 1 is clamped and tensioned by the clamp spring 7 and bent by the movement of the anvil 9. However, before the optical fiber 1 is scored with the blade 6, a secondary anvil 38 is applied in direction of arrow C, bending the fiber in the opposite direction to the first anvil 9, as shown in Fig. 7a, and so introduces shear forces into the fiber.
  • the fiber is scored by the blade on the outside of a bend at a point 37, it cleaves with an angled end.
  • the secondary anvil 38 consists of a narrow tip 39, mounted on a pivot 40, with an extension arm 41 and a spring activation element 42, as shown in side-view and end-view in Figs. 7b, 7c, respectively.
  • the secondary anvil is activated by depressing the spring 42 which causes the anvil 38 to rotate around its pivot 40 to bring its tip 39 into contact with the fiber 1 , bending it with a force F related to the strength of the spring 42.
  • a lever 43 is moved in the direction of arrow II to introduce a shim 44 underneath a shoulder 45 on the vertical rod 31.
  • the middle plate 4 is lowered and the fiber 1 is clamped and tensioned by the clamp spring 7 and bent by the anvil 9.
  • the activation rod 34 pushes down on the vertical rod 31 such that its shoulder 45 contacts the shim 44, bending the activation spring 42 which causes the secondary anvil 38 to rotate, exerting a shear force F in the optical fiber 1.
  • Further closing the tool will further lower the vertical rod 31 which will cause it to contact the screw 30 and so rotate the bracket 26a, b and hence cause the blade 6 to score the fiber 1 , giving an angled cleave.
  • the top edge 39 of the secondary anvil 38 is preferably tipped with a compliant material 46 such as a hard rubber; the spring element 42 is replaced by a continuation of the extension arm 41.
  • the shim 44 is introduced by the lever 43 so that on closing the casing element 3a, the vertical rod 31 brings about a known displacement of the end of the extension arm 41. This displacement rotates the secondary anvil 38 around its pivot so that its edge 39 is moved a controlled distance towards and into contact with the fibers 1 , with the compliant material 46 on its tip coming into contact with each fiber in the ribbon.
  • the compliant material 46 is compressed by a given amount at its point of contact with each fiber, so applying a bending force F to each fiber in the ribbon which will be equal and independent. Therefore, each fiber in the ribbon will experience the same stresses and will be cleaved by the blade 6 with an equal end angle. Both angled and perpendicular cleaves can be achieved from this tool respectively, either by applying or not applying the secondary anvil 38 using the lever 43.
  • Another way of creating cleaved ends which are angled is to apply non-symmetric bending to the fiber when it is clamped and tensioned.
  • This can be achieved by rotating the anvil 9 so that its two arms 25a, 25b are not perpendicular to the fiber of fibers, as shown in side- and bottom- views in Fig. 8b.
  • a lever 47 is rotated in the direction of arrow III so that the arms of the anvil 9 are either perpendicular to the fibers 1 (Fig. 8a) , giving perpendicular cleaves, or at an angle to the fibers 1 (Fig. 8b) , giving angled cleaves.
  • the tip of the two arms 25a, 25b are coated with a compliant material such as rubber.
  • a further way of cleaving angled ends is to bend the clamped and tensioned fiber or fibers 1 over an anvil 9 which has only one arm, with the blade 6 scoring the fiber or fibers at a point 48 away from the point of application of the anvil 9.
  • This is achieved in Fig. 9 by using a lever 49 to withdraw one arm of the anvil 25a in the direction of arrow IV, with the fiber bent over the remaining arm 25b.
  • the fiber is scored at a point 48 to give angled cleaves, Fig.9b.
  • the lever 54 is not applied, the anvil 9 possesses two arms 25a, 25b and gives rise to a perpendicular cleave, Fig.9a.
  • An alternate way of applying non-symmetric bending to cleave angled ends on a clamped and tensioned fiber is to bend the fiber 1 over an anvil 9 which has non-parallel arms 25a, 25b, as shown in bottom view in Fig.10b, preferably whose ends are tipped with a compliant material such as rubber.
  • a separation wedge 48 is applied in the direction of arrow V forcing apart the two annular sections 49a, 49b, so that they rotate around the central pin of the anvil 9. Consequently the arms of the anvil 25a, 25b are rotated with respect to each other and the fibers 1 , leading to shear stresses in the fibers and angled cleaved ends.
  • a spring 50 ensures that the arms of the anvil 25a, 25b, are parallel when the separation wedge is not engaged, as shown in Fig 10a leading to perpendicular cleaved ends.
  • the shear stresses should consequently be in the plane of fiber ribbon whereas the previously discussed angled cleaving techniques should give shear stresses perpendicular to the plane of the fiber ribbon and perpendicular to the fibers.
  • the angled plane of cleavage is rotated by 90 degrees compared with previously discussed angled cleaving techniques which may offer significant benefits with regard to polarized light and other applications.
  • Yet another way of cleaving angled ends is to apply torsion to the fiber or fibers 1 in addition to the tension and bending forces, Fig 11.
  • This can be achieved by clamping, tensioning and bending the fiber or fibers 1 by closing the tool as above, and then rotating the clamps with respect to each other before the fiber or fibers 1 are scored with the blade 6.
  • the ground edges 16a, 16b, around which the steel rollers 14a, 14b rotate, are located in two location plates 69a, 69b, with matching grooves 70a, 70b.
  • the opposite ends of the location plates are rested on sharp edges 51a, 51b, around which they can rotate in the direction of the arrows VI, as shown in Fig. 11.
  • the other ends of the location plates are supported on springs 53a, 53b.
  • the fiber 1 is clamped onto the clamping faces 15a, 15b and the springs 53a, 53b are progressively compressed, rotating the location plates 69a, 69b such that the faces of the rollers 15a, 15b are rotated in opposite directions, hence rotating the clamped and tensioned fiber or fibers 1.
  • the total angular rotation of the clamps, and hence the end angles cleaved, are controlled by stops 54a, 54b which prevent further rotation of the clamping faces 15a, 15b. Cleaving is brought about by scoring the fiber or fibers with the blade 6, giving an angled cleave when the clamping faces 15a, 15b are rotated.
  • This tool is also capable of cleaving perpendicular ends by preventing the rotation of the clamping faces by introducing shims 55a, 55b in the direction of arrows VII between the bottom faces 52a, 52b of the location plates and the stops 54a, 54b.
  • the ribbon version of this tool will cleave angled or perpendicular ends onto single or multiple optical fibers.
  • All of the above functions of the tool can be achieved by operating the tool as a benchtop tool, where the lower block 3 is placed on a bench and the handle plate 19a and middle plate 4 are pressed downwards to clamp, tension, bend and score the fiber or fibers 1 , hence cleaving them.
  • the tool can be mounted on a tripod using a fixing in the lower block 3 such as a thread which is compatible with a camera tripod.
  • the tool can be held in the hand and squeezed together to clamp, tension, bend and score the fiber or fibers 1 , hence cleaving them.
  • Removal of the offcuts of fiber or fibers remaining after the fibers have been cleaved can optionally be achieved by electrostatic attraction between the fiber offcut and a substantially electrically insulating material such as rubber or plastic, whereby optical fibers naturally acquire an electrostatic charge after exposure to the atmosphere for a few seconds.
  • Means can be provided to remove the fiber offcut or offcuts from the tool, whereby a substantially electrically insulating material is pressed gently onto the fiber offcut which electrostatically sticks to the insulating material and is therefore easily removed from the cleaving tool.
  • the insulating material is in the form of a smooth rubber pad and is preferably made of silicone rubber with a Shore A hardness of between 20 and 70.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Light Guides In General And Applications Therefor (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Abstract

Deux paires de surfaces de serrage (8a, 15a, 8b, 15b) immobilisent une section de fibre optique (1) entre deux points. Les surfaces de serrage peuvent être réalisées en un matériau élastique, pour serrer toutes les fibres en formant un ruban avec elles. La ou les fibres sont mises sous tension par un étirement déterminé par la compression d'un ressort à lames (7) constituant une paire supérieure (8a, 8b) de surfaces de serrage. La paire inférieure de surfaces de serrage (15a, 15b) est constituée par une paire de blocs à roulements rotatifs (14a, 14b) qui suivent le mouvement du ressort supérieur, pour permettre un allongement longitudinal de la ou des fibres serrées. Les fibres sous tension sont ensuite déplacées latéralement par pliage sur une enclume (9) à deux bras pour en éliminer l'essentiel des contraintes de cisaillement. Puis, les fibres sont entaillées par une lame tranchante (6) sur le côté de la fibre opposé à l'enclume, la lame étant disposée de manière à former un angle aigu par rapport à son sens de déplacement vers la ou les fibres sous tension. La très lente pénétration de la lame dans la fibre par suite de cet angle aigu ne produit pas de forces additionnelles de pliage significatives et donne des extrémités sectionnées sensiblement à la perpendiculaire.
PCT/GB1996/000919 1995-04-20 1996-04-17 Ameliorations concernant le sectionnement de fibres optiques WO1996033430A1 (fr)

Applications Claiming Priority (4)

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GBGB9508035.4A GB9508035D0 (en) 1995-04-20 1995-04-20 Improvements in and relating to fiber optic cleaving methods and devices
GB9508035.4 1995-04-20
GB9605587.6 1996-03-16
GBGB9605587.6A GB9605587D0 (en) 1996-03-16 1996-03-16 Improvements in and relating to fiber optic cleaning methods and devices

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998045676A1 (fr) * 1997-04-04 1998-10-15 Siemens Aktiengesellschaft Procede et dispositif pour tester la resistance a la traction de fibres epissurees dans des appareils d'epissurage de fibres
WO1998054608A1 (fr) * 1997-05-30 1998-12-03 Oxford Fiber Optic Tools Limited Outil de clivage oblique de fibres optiques ou autres
DE10043173A1 (de) * 2000-09-01 2002-03-28 Fci Automotive Deutschland Gmb Vorrichtung zum Schneiden von polymeren optischen Faserlichtwellenleitern (POF-LWL)
EP1061387A3 (fr) * 1999-06-17 2004-02-25 Lucent Technologies Inc. Système comprenant une fibre optique plastique
GB2368134B (en) * 2000-10-09 2004-06-02 Chynoptics Technologies Inc Fiber optic switching apparatus
EP1791009A1 (fr) * 2005-11-05 2007-05-30 Schäfer Werkzeug- und Sondermaschinenbau GmbH Procédé destiné à sectionner une fibre optique revêtue
EP1936413A1 (fr) * 2005-02-02 2008-06-25 Tyco Electronics Raychem NV Dispositif de clivage de fibres optiques
RU2589524C2 (ru) * 2010-06-28 2016-07-10 Нано-Пресижен Продактс, Инк. Заранее определенное разрушение оптического волокна
CN109655978A (zh) * 2019-02-22 2019-04-19 合肥科塑信息科技有限公司 一种微型串行scsi宽带高速传输的并行光收发组件
WO2020058677A1 (fr) * 2018-09-21 2020-03-26 Oxford Fiber Ltd Coupe-fibre optique
US11036007B2 (en) 2016-06-16 2021-06-15 Technologies O'fiberty Inc. Fiber cleaver
CN113841074A (zh) * 2019-05-24 2021-12-24 日东电工株式会社 切断治具和光纤的切断方法
CN118010526A (zh) * 2024-04-09 2024-05-10 索拉特特种玻璃(江苏)股份有限公司 一种超白压延玻璃四点弯曲试验机
CN119825486A (zh) * 2025-01-14 2025-04-15 哈尔滨工业大学 具有半劈缝冷却结构的叶片和发动机

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2021094A (en) * 1978-05-12 1979-11-28 Bowthorpe Hellermann Ltd Optical fiber breaker tool
US4322025A (en) * 1980-09-03 1982-03-30 Amp Incorporated Tool for cutting optical fibers
US4557049A (en) * 1982-04-15 1985-12-10 Gte Products Corporation Hand held fiber optic cleaving tool
EP0208415A1 (fr) * 1985-07-10 1987-01-14 THE GENERAL ELECTRIC COMPANY, p.l.c. Procédé et dispositif de clivage de fibres optiques
GB2186567A (en) * 1986-02-06 1987-08-19 Pirelli Cavi Spa Device for cutting optical fibres
US5123581A (en) * 1991-01-04 1992-06-23 Bell Communications Research, Inc. Oblique fracturing of optical fibers by offset shearing
EP0579521A1 (fr) * 1992-07-17 1994-01-19 Framatome Connectors International Procédé et dispositif de clivage d'une fibre optique
EP0637763A1 (fr) * 1993-08-04 1995-02-08 AT&T Corp. Dispositif de clivage oblique de fibres optiques

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2021094A (en) * 1978-05-12 1979-11-28 Bowthorpe Hellermann Ltd Optical fiber breaker tool
US4322025A (en) * 1980-09-03 1982-03-30 Amp Incorporated Tool for cutting optical fibers
US4557049A (en) * 1982-04-15 1985-12-10 Gte Products Corporation Hand held fiber optic cleaving tool
EP0208415A1 (fr) * 1985-07-10 1987-01-14 THE GENERAL ELECTRIC COMPANY, p.l.c. Procédé et dispositif de clivage de fibres optiques
GB2186567A (en) * 1986-02-06 1987-08-19 Pirelli Cavi Spa Device for cutting optical fibres
US5123581A (en) * 1991-01-04 1992-06-23 Bell Communications Research, Inc. Oblique fracturing of optical fibers by offset shearing
EP0579521A1 (fr) * 1992-07-17 1994-01-19 Framatome Connectors International Procédé et dispositif de clivage d'une fibre optique
EP0637763A1 (fr) * 1993-08-04 1995-02-08 AT&T Corp. Dispositif de clivage oblique de fibres optiques

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
H. SCHMIDT-KLOIBER: "A simple device for the preparation of end-surfaces of single optical fibres up to diameters of 0.7 mm", JOURNAL OF PHYSICS E: SCIENTIFIC INSTRUMENTS, vol. 17, no. 12, December 1984 (1984-12-01), WOLVERHAMPTON, GB, pages 1105 - 1106, XP002009296 *

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US6561019B1 (en) 1997-04-04 2003-05-13 Siemens Aktiengesellschaft Method and apparatus for tensile testing a spliced connection of fibers in a fiber splicing device
WO1998045676A1 (fr) * 1997-04-04 1998-10-15 Siemens Aktiengesellschaft Procede et dispositif pour tester la resistance a la traction de fibres epissurees dans des appareils d'epissurage de fibres
WO1998054608A1 (fr) * 1997-05-30 1998-12-03 Oxford Fiber Optic Tools Limited Outil de clivage oblique de fibres optiques ou autres
EP1061387A3 (fr) * 1999-06-17 2004-02-25 Lucent Technologies Inc. Système comprenant une fibre optique plastique
DE10043173A1 (de) * 2000-09-01 2002-03-28 Fci Automotive Deutschland Gmb Vorrichtung zum Schneiden von polymeren optischen Faserlichtwellenleitern (POF-LWL)
GB2368134B (en) * 2000-10-09 2004-06-02 Chynoptics Technologies Inc Fiber optic switching apparatus
EP1936413A1 (fr) * 2005-02-02 2008-06-25 Tyco Electronics Raychem NV Dispositif de clivage de fibres optiques
NO341080B1 (no) * 2005-02-02 2017-08-21 Tyco Electronics Raychem Bvba Kappeinnretning for optiske fibre
EP1791009A1 (fr) * 2005-11-05 2007-05-30 Schäfer Werkzeug- und Sondermaschinenbau GmbH Procédé destiné à sectionner une fibre optique revêtue
RU2589524C2 (ru) * 2010-06-28 2016-07-10 Нано-Пресижен Продактс, Инк. Заранее определенное разрушение оптического волокна
US11036007B2 (en) 2016-06-16 2021-06-15 Technologies O'fiberty Inc. Fiber cleaver
GB2578520B (en) * 2018-09-21 2022-04-20 Oxford Fiber Ltd Optical fibre cleaving tool
GB2578520A (en) * 2018-09-21 2020-05-13 Oxford Fiber Ltd Optical fibre cleaving tool
WO2020058677A1 (fr) * 2018-09-21 2020-03-26 Oxford Fiber Ltd Coupe-fibre optique
CN109655978A (zh) * 2019-02-22 2019-04-19 合肥科塑信息科技有限公司 一种微型串行scsi宽带高速传输的并行光收发组件
CN113841074A (zh) * 2019-05-24 2021-12-24 日东电工株式会社 切断治具和光纤的切断方法
EP3978970A4 (fr) * 2019-05-24 2023-07-19 Nitto Denko Corporation Outil de coupe et procédé de découpe de fibre optique
US12158608B2 (en) 2019-05-24 2024-12-03 Nitto Denko Corporation Cutting jig and cutting method of optical fiber
CN118010526A (zh) * 2024-04-09 2024-05-10 索拉特特种玻璃(江苏)股份有限公司 一种超白压延玻璃四点弯曲试验机
CN119825486A (zh) * 2025-01-14 2025-04-15 哈尔滨工业大学 具有半劈缝冷却结构的叶片和发动机

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