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A close-up of the cleave assembly on the LDC450B. 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 Ø200 µm to Ø800 µm
• Flat Cleaves
• 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
• Handheld Controller for Setting Cleave Parameters (See Controller Tab for Details)
• Replacement Components Sold Separately Below
• Holding Blocks and Inserts are Compatible with Other Vytran^® Systems:
  • LDC401 and LDC401A Large-Diameter Fiber Cleavers
  • 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 Ø200 µm to Ø800 µm
• Choose Top and Bottom Inserts (Two Top Inserts and Two Bottom Inserts are Required;
  See Fiber Holder Inserts Tab for More Information)

The LDC450B Portable Large-Diameter Fiber Cleaver precisely cleaves fibers with claddings from 200 µm to 800 µm in diameter, and is designed to produce flat cleaves perpendicular to the length of the fiber. For ease of use and versatility in both manufacturing and research environments, this fiber cleaver features a rechargeable battery and includes our VYT300C Handheld Controller. 

The cleaver uses 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 cleaver also has 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). The 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 cleaver uses 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 LDC450B cleaver is 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 cleaved, as well as to aid to install them in the fiber holding blocks. Two top and two bottom inserts are required to operate the fiber cleaver.

To cleave Ø80 µm to Ø1.25 mm fibers, Thorlabs offers the LDC401 and LDC401A Large-Diameter Fiber Cleavers, which produce flat and angled cleaves, respectively. Both are equipped with a vacuum pump to aid in positioning smaller fibers with diameters <200 µm. In addition to the portable large-diameter fiber cleaver, 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 LDC450B cleaver are also compatible with these other fiber processing systems, making it easy to move the fiber between stations.

Programmable Cleave Parameters

This portable, large-diameter fiber cleaver is 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 handset 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

• Introduction
• Fiber Holder Insert Selection Chart
• Fiber Holder Assembly and Installation

Introduction

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. Fiber holder inserts designed for fibers smaller than Ø1000 µm have vacuum holes that, when used with a Vytran system that includes a vacuum pump for the fiber holding blocks, can aid in aligning small fibers within the groove. Note that the LDC450B does not include a vacuum pump, and therefore, does not take advantage of this feature.  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 a Vytran system that includes a vacuum pump for the fiber holding blocks. Note that the LDC450B cleaver does not include a vacuum pump.
• 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 LDC450B cleaver 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.

Tension-and-Scribe Cleave Process

The LDC450B cleaver 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. 

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 handset 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	Standard Process	Sub-Critical Process	Micrometer Backstop
Single Mode Fiber		-	-
Multimode Fiber		-	-
Thick-Walled Capillary Tubing (Wall Thickness at Least 10% of Diameter)	-	-
Thin-Walled Capillary Tubing (Wall Thickness <10% of Diameter)	-
PM Fiber, Fiber Cladding ≤Ø400 µm		-
PM Fiber, Fiber Cladding >Ø400 µm	-
PCF	-

Handset Controller GUI Interface

The VYT300C handset controller is included with the LDC450B portable, large-diameter fiber cleaver. This controller is also compatible with the LDC401 and LDC401A Vytran large-diameter fiber cleavers, as well as Vytran PTR fiber recoaters and proof testers. One handset controller can be used to configure parameters on multiple fiber processing units in succession. Full instructions for using the handset controller can be found in the manual. The screenshots below highlight key features of the graphical user interface.

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The initial screen on VYT300C handset controller prompts the user to load the fiber, as well as providing the options to start a cleave with the displayed parameters and to home the fiber holding blocks. Other menus can be accessed by swiping the touchscreen left or right, or by tapping the options at the top of the screen.

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During a cleave, the handset controller monitors the cleave tension and the number of cleave peck cycles. It also displays parameters defined in the edit tab.

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The Tools Screen provides several utilities that are used for maintenance or troubleshooting.

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The Edit menu shows parameters that can be configured by the user. These parameters are the same as those that can be edited using the tablet controller.

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The handset controller can open, save, delete, export, and import files containing parameters for compatible systems. Exporting or importing a file will require a memory device to be connected to the Program Port of the handset controller.

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Fiber files can be saved onto the internal storage of the handset controller.