Vytran® Fiber Cleavers for Ø80 µm to Ø1.25 mm Cladding Fibers

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A close-up of the cleave assembly on the LDC401A. A clamping screw on the top of each holding block can be tightened to provide extra clamping force for gripping fibers with outer diameters ≥500 µm. Magnets in each holding block provide sufficient force for clamping smaller fiber diameters.

Features

• Cleave Glass Fibers with Claddings from Ø80 µm to Ø1.25 mm
• Flat Cleaves or Angled Cleaves up to 15°
• Programmable Processes for a Wide Variety of Fibers:
  • Single Mode, Multimode, and Polarization-Maintaining Fibers
  • Capillary Tubes*
  • Photonic Crystal Fiber (PCF)*
  • Microstructured Fibers*
  • Non-Circular Fibers
• Touchscreen Tablet for Setting Cleave Parameters (See Tablet Controller Tab for Details)
• Holding Blocks and Inserts are Compatible with Other Vytran^® Systems:
  • FPS300 Cleaning and Stripping Station
  • LFS4100 Splicer
  • GPX3400 and GPX3600 Glass Fiber Processing Stations
  • GPX4000LZ CO₂ Laser Glass Processor

Build Your System

• Large-Diameter Fiber Cleaver for Fibers with Claddings from Ø80 µm to Ø1.25 mm
• Choose Top and Bottom Inserts (Two Top Inserts and Two Bottom Inserts are Required; See Fiber Holder Inserts Tab for More Information)

These Vytran Fiber Cleavers precisely cleave fibers with claddings from 80 µm to 1.25 mm in diameter. The LDC401 is designed to produce flat cleaves perpendicular to the length of the fiber, while the LDC401A has a rotation stage module for creating angled cleaves up to 15°.*

The cleavers use the "tension-and-scribe" cleaving process, where tension is applied along the length of the fiber followed by an automatic scribing process utilizing a diamond cleave blade. After the blade scribes the fiber, tension is maintained, causing the scribe to propagate across the fiber width and complete the cleave. The LDC401A accomplishes angled cleaves by using the rotation stage to apply torsion to the fiber prior to scribing; the cleave plane will be perpendicular to the maximum resultant stress created by the combined tension and torsion applied to the fiber.

The cleavers have settings to carry out an automated "sub-critical" scribe process designed to improve the cleave quality in specialty fibers, such as photonic crystal fiber (PCF), microstructured fibers, capillary tubes, or highly stressed fibers (multimode or polarization maintaining). Each cleaver is equipped with a flat-tipped micrometer backstop, which can help improve end-face quality when performing low-tension cleaves. See the Cleaving Guide tab for details.

The cleavers use a diamond blade for scribing the fiber. When used with proper cleave parameters, a single location on the blade can provide up to 5,000 cleaves (dependent on the cladding properties of the fiber being cleaved). The cleaver is designed so that the cleave blade can be repositioned approximately nine times before replacement (assuming proper cleave parameters and usage that does not cause unexpected damage to the blade). We only recommend using these cleavers with fibers that have a glass cladding; other materials, such as plastic, will rapidly degrade or damage the blade. Replacement blades are available separately below.

Accessories
The LDC401 and LDC401A are designed to accept Fiber Holder Inserts that can clamp a variety of outer diameters. Our selection of top and bottom inserts are available separately below, listed with the maximum fiber sizes accepted by each insert. The Fiber Holder Inserts tab has a selection guide to aid in choosing which pairs of fiber holder inserts are required based on the diameter of the fiber to be leaved. Two top and two bottom inserts are required to operate the fiber cleaver.

In addition to the large-diameter fiber cleavers, we offer the FPS300 Stripping and Cleaning Station, the LFS4100 Fiber Splicer, GPX4000LZ CO₂ Laser Glass Processor and the GPX3400 and GPX3600 Glass Fiber Processing Stations. Many of the fiber holder inserts that are compatible with the LDC401 and LDC401A are also compatible with these fiber processing systems, making it easy to move the fiber between stations.

* It may not be possible to create clean, angled cleaves in specialty fibers with large "air-fill" fractions due to the structural properties of the fiber.

Programmable Cleave Parameters

These large-diameter fiber cleavers are designed to provide easy operation when performing simple cleaves but still support customized processing for more complicated cleaves involving specialty fibers. A complete list of modifiable parameters is listed below. The majority of users will only need to enter the Fiber Diameter (cladding), Cleave Tension, and Pre-Cleave Advance while leaving the rest of the parameters set to their default values. To further simplify the process, the tablet controller features an autoset function that will estimate an appropriate Cleave Tension and Pre-Cleave Advance based on the fiber diameter, although these values can be adjusted by the user if necessary.

Fiber Holder Insert Selection Guide

Fiber Holder Inserts, which are designed to hold various sized fibers within the cleaver, must be purchased separately. The bottom inserts have V-grooves to hold the fiber, while the top inserts each feature a recessed, flat surface that clamps the fiber against the V-groove in the bottom insert. Each top and bottom insert is sold individually, as the fiber diameter clamped by the left and right holding blocks may not be the same. Two top inserts and two bottom inserts are required to operate the cleaver.

The table below indicates the maximum and minimum diameters that can be accommodated by different combinations of top and bottom inserts. It also indicates how far offset the fiber will be for recommended combinations of top and bottom inserts. Note that the fiber outer diameter may be the fiber cladding, jacket, or buffer. If one side of the fiber is being discarded, it is preferable to clamp onto the cladding of this section except in special cases (such as non-circular fiber) where the coating or buffer may be preferable. Sections of fiber that are not being discarded should always be clamped on the coating or buffer in order to avoid damaging the glass. This may require different sets of fiber holder inserts to be used in the left and right holding blocks. In this case, it is important to minimize the difference in the offsets introduced by the left and right sets of inserts when attempting to produce perpendicular, flat cleaves.

Each V-groove can accommodate a range of fiber sizes.

Fiber Holder Insert Selection Chart

1. First, select the bottom insert that matches your fiber size most closely.
   Example: For an Ø800 µm fiber, the VHD750 insert is the closest match, since it is only 50 µm smaller.
2. On the chart below, look to the right of your chosen bottom insert. Select a compatible top insert based on the fiber diameter size range shown in each cell.
   Example: For the Ø800 µm example fiber from step 1, the green cell is in the 750 µm groove column for the VHA05 top insert which has two grooves. The numbers listed in the green cell indicate that this combination of inserts is good for fibers from 728 to 963 µm in diameter. Our Ø800 µm fiber is within this range, so this is a good choice. There are several other options as well that will accommodate an Ø800 µm fiber as well, but the green shading in the chart indicates that the 750 µm groove in the VHA05 provides the best fit. 
3. The second line of numbers in each cell shows the range of offsets that can be expected for any given combination of top and bottom inserts. When selecting inserts for the right and left fiber holding blocks, try to minimize the offsets between the pairs of inserts on each side.
   Example: If we choose a VHD750 bottom insert and the Ø750 µm groove in the VHA05 top insert, we can use fiber as small as 728 µm, in which case the center of the fiber would sit 23 µm below the surface of the bottom insert. We could also clamp a fiber as large as 963 µm, in which case the center of the fiber would sit 213 µm above the surface of the bottom insert. We could interpolate to find the offset experienced by our hypothetical 800 µm fiber, but it turns out that in the 60° V-groove on these inserts, the offset is equal to the diameter difference. So in our example, that means that the center of our fiber is going to sit 50 µm above the bottom insert surface, since it is 50 µm larger than the fiber that the bottom insert was designed for (800 - 750 = 50).
4. Holding blocks designed for fibers less than Ø1000 µm have vacuum holes, designed to aid in aligning small fiber within the groove, while bottom inserts for fibers of Ø1000 µm or larger do not have these holes. The LDC4010 and LDC401A each have a vacuum pump that provides a small holding force via these holes, keeping small fibers in place as the clamps are lowered. Inserts with vacuum holes are indicated by a superscript "b" in the table below.

• These inserts have two grooves, one on each side, that each accommodate a different range of fiber sizes, except for the VHA00, which has a flat surface on one side that can be used to clamp the smallest fiber sizes.
• These bottom inserts have vacuum holes to aid in aligning small fibers when used with the large-diameter fiber cleavers.
• These are transfer inserts. When used with the VHT1 transfer clamp, they allow the fiber to be transferred between compatible stripping, cleaning, cleaving, splicing, and tapering stations without losing registration of the fiber tip location relative to the edges of the fiber holding block.

Tension-and-Scribe Cleave Process

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An illustration of the tension-and-scribe method as used by the LDC401 and LDC401A to produce a flat cleave. Tension is applied along the optical axis of the fiber prior to cleaving. A diamond blade then scribes the fiber, and the tension causes the scribe to propagate across the fiber in a plane that is orthogonal to the direction of the tension.

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An illustration of the tension-and-scribe method as used by the LDC401A to produce an angled cleave. Tension and torsion are applied simultaneously to the fiber prior to cleaving. When the blade scribes the fiber, the scribe propagates across the fiber orthogonally to the direction of the maximum resultant stress produced by the combined tension and torsion, producing an angled cleave.

Tension-and-Scribe Cleave Process

The LDC401 cleavers use the "tension-and-scribe" cleaving process, where tension is applied along the length of the fiber followed by an automatic scribing process utilizing a diamond blade. After the blade scribes the fiber, tension is maintained, causing the scribe to propagate across the fiber width and complete the cleave. Angled cleaves are accomplished in the LDC401A by using the rotation stage to apply torsion to the fiber, starting prior to commencing the "tension-and-scribe" process. The cleave plane will then be perpendicular to the maximum resultant stress created by the combined tension and torsion applied to the fiber.

Sub-Critical Process for Cleaving Specialty Fibers

Certain specialty fibers, such as photonic crystal fiber (PCF), microstructured fibers, capillary tubes, or highly stressed fibers (multimode or polarization maintaining) may require special parameters in order to create clean cleaves at the desired angle. These Vytran^® fiber cleavers can be programmed with a "sub-critical" cleave process in order to produce high-quality cleaves for these fiber types.

For these cleaves, the initial tension applied to the fiber is lower than what would be required for the standard "tension-and-scribe" process. The included micrometer backstop prevents the fiber from bending when it is scribed at this lower tension. After the scribe, the tension is slowly, incrementally increased, which serves to propagate the scribe across the fiber and complete the cleave. Parameters for this process can be adjusted using the tablet controller, including the starting and ending tension and how fast the tension is increased after the initial scribe.

Cleaving Guide

The following information is intended to provide a starting point when selecting the best process to use for cleaving different types of fiber. To achieve the best possible cleave results, further experimentation is typically required to fine-tune the cleave parameters for each specific fiber type.

Standard Process: The tension-and-scribe method where a constant tension is applied to the fiber, the fiber is scribed, and the tension causes the scribe to propagate across the fiber to produce the cleave.

Sub-Critical Process: This process starts with a lower tension applied to the fiber than required by the standard cleaving process. After the fiber is scribed, the tension is slowly increased until the scribe propagates across the fiber and the cleave is complete. This can improve the cleave quality in highly stressed or specialty fibers.

Micrometer Backstop: The tip of the micrometer is positioned so that it just touches the fiber, providing a surface that prevents the fiber from deforming when contacted by the cleave blade during scribing. It is particularly useful when cleaving large-diameter fibers or when using the lower-tension sub-critical process.

Fiber Type	Cleave Type	Standard Process	Sub-Critical Process	Micrometer Backstop
Fiber with Cladding <Ø800 µm	Flat or Angleda		-	-
Fiber with Cladding ≥Ø800 µm	Flat or Angleda		May Be Necessary	Use if the Cleave Blade is Pushing the Fiber Forwards without Cleaving
Multimode Fiber	Flat		-	-
	Angleda	-		Use if Fiber Cladding is >Ø400 µm
Thick-Walled Capillary Tubing (Wall Thickness at Least 10% of Diameter)	Flat or Angleda	-	-
Thin-Walled Capillary Tubing (Wall Thickness <10% of Diameter)	Flat or Angleda	-
PM Fiber	Flat	Use if Fiber Cladding is ≤Ø400 µm	Use if Fiber Cladding is >Ø400 µm
	Angleda	-
PCF	Flat or Angleda	-

• Only the LDC401A can be used to produce angled cleaves.

Tablet Controller GUI Interface

Each LDC401 and LDC401A includes a touchscreen tablet controller, which provides a simple interface for configuring, controlling, and monitoring cleaver operation. The screenshots below highlight key features of the graphical user interface. Additionally, the user can enter passwords and set permissions, allowing only authorized users to access and change the LDC401 or LDC401A settings. The controller can be operated in one of four languages: English, French, Russian, or Chinese.

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Home Screen
The LDC401 home screen provides a status bar, tool bar, start button, and a button to view or edit the parameters. The symbols on the right of the screen make up the LDC Widget.
Top row, left to right: left FHB inserts, FHB offset in mm, cleave blade index, cleave counter, right FHB inserts, rotation angle.
Bottom row, left to right: target tension, fiber cladding and jacket diameter, micrometer backstop position, regular or sub-critical cleave, ready/busy indicator.

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Cleave Parameters
This screen allows the user to access and change all cleave parameters. The current setting is displayed next to the parameter name.

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Cleave Process Screen
Once the cleave process is started, the Cleave Screen is displayed. This screen updates dynamically as the cleave sequence progresses. A typical sequence consists of loading the fiber, pulling tension, cleaving the fiber, and then unloading (although the user can go straight to the tension stage by pressing start when the left FHB lid is closed). This screen shows the LDC widget, allowing the user to make final adjustments to parameters before the cleave.

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Automatic Settings
Auto Parameter will generate a basic set of suggested theoretical cleave parameters based on the Fiber Diameter (and if required, the Desired Cleave Angle). The user can edit each parameter by touching the item in the list.

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Motor Control
This window allows the user to adjust the desired position of the fiber holding block, either by typing in a new setting, using the slider, or using the arrow buttons beneath the slider. While this window is for the fiber holding block, similar windows are available to set the position of the motor that drives the cleave blade and the rotation stage for angle cleaves (LDC401A only).

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Blade Service
The blade service window allows the user to move the blade between its service position and its home position. The screen includes a list of the parameters needed to manage the blade setup. The cleave counter counts the number of cleaves performed by the blade in a given position. Each time the blade is replaced or moved so that a new part of the blade is in use, the cleave counter should be reset to zero and the cleave blade index incremented by 1. These can be done by tapping the boxes next to "Cleave Blade Index" and "Cleave Counter."