THORLABS Vytran LDC401, Руководство пользователя

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LDC401 & LDC401A Automated Cleavers Chapter 7: Cleaving
Rev B, July 19, 2017 Page 19
7.9. Specialty Cleave Process
Two additional process capabilities are available on these cleavers. These processes are primarily utilized for
specialty fiber cleaving such as microstructured fiber, highly stressed fibers (usually PM), or capillary tubing. The
specialty fiber processes are used to improve end face quality but require the execution of additional steps.
7.9.1. Subcritical Process
The Subcritical Process should be used in the following circumstances:

When cleaving microstructured fiber such as PCF (photonic crystal fiber) or PBF (photonic band gap fiber).

When cleaving capillary tubing whose wall thickness is less than 10% of its diameter.

When cleaving PM fiber that has a cladding more than 400 µm in diameter.

When angle cleaving multimode fiber or PM fiber.

When cleaving fiber with a cladding diameter of 800 µm or larger and a high-quality end face is required.
The Subcritical Process applies a tension that is lower than that required for a regular cleave. The blade then scribes
the fiber and the tension is incrementally increased to propagate the scribe and produce the cleave. Since the crack
is allowed to propagate relatively slowly with little driving force, a smoother cleave surface is produced. To activate
the Subcritical Process, open the Parameter Select screen, select the Sub-Critical Cleave Process parameter and
select Enable. When enabled, three additional parameter values must be specified. These parameters are Re-
Tension Level, Post-Scribe Pause, and Re-Tension Pause. Please refer to Section 9.8 for a definition of these
Parameters. In addition to specifying these new parameter values, two existing parameter values may require
adjustment. These are Cleave Tension and Cleave Oscillation Counter (or Cleave Peck Cycles). Experimentation
will be required in order to set these parameters. A general rule is that the Cleave Tension should be lowered to
60% of the Auto Parameter value and the Cleave Oscillation Counter should be set at 30. Optimal settings for these
values are achieved when then the Cleave Blade will scribe the fiber in the last few oscillations without causing the
cleave to propagate immediately or the fiber to bow significantly. Please note: all Subcritical Process parameter
settings are VERY fiber dependent.
7.9.2. Micrometer Backstop
The Micrometer Backstop may be helpful in the following circumstances:

When cleaving large fiber (cladding greater than 800 µm in diameter) if the Cleave Blade appears to be
pushing the fiber forwards without cleaving it.

When Angle-cleaving multimode fiber that is more than 250 µm in diameter.

When cleaving capillary tubing.

When cleaving PM fiber.

When cleaving PCF or PBF.
Figure 19 The Micrometer Backstop Acting as a Backstop to a Fiber