Recoat Process; Loading The Fiber - THORLABS vytran PTR406 User Manual

Fiber Recoaters with Linear Proof Testers

Recoat Process

The purpose of the recoat is to maintain the strength and flexibility of the fiber or fusion splice by protecting the
glass surface from damage. It should be noted that recoating a splice does not make the splice stronger.
To recoat a fusion splice, the section of exposed fiber is placed in a quartz recoat mold assembly. External holding
fixtures secure the fiber, centering it within the recoat assembly. To allow for tolerance variations from fiber
manufacturers, the diameter of the recoat mold cavity is generally specified to be slightly larger than the nominal
outside coating diameter (e.g. 280 µm for a nominal 250 µm coating).
The recoat process maintains a near original fiber diameter and delivers a flexible fusion splice that can be handled
or tightly coiled as if no splice were present. The integral fiber holding fixtures ensure that the fiber strength is not
degraded by the recoat process.
9.1.

Loading the Fiber

Fiber guides are mounted on each side of the fiber holding block inserts to aid in loading the fiber into the fiber
folding blocks. Vacuum to the fiber holding blocks is automatically turned on when one of the holding tops is raised.
Make sure that the fiber holding block inserts are sized correctly for the fiber to be recoated. The size, in microns,
is labeled on the outside surface of the fiber guides.
To position a fiber for recoating, use the following procedures:
1. Raise the recoat top and both holding block tops.
2. Make sure both quartz plates are clean and that the injection port has enough UV material for the recoat
(Manual Injection) or that the injection system is purged (PTR406/PTR406B).
3. Hold the section of fiber to be recoated straight between two hands, making sure not to touch the exposed
section of fiber (a total separation of approximately 8 inches is a convenient distance).
4. Lower the fiber into both sets of fiber guides until the fiber sits on the rubber inserts.
5. Make sure the stripped section of fiber is centered left-to-right in the recoat mold and close one of the fiber
holding block tops. A free finger can be used to flip the top closed as the rubber inserts will not damage the
coating.
6. Make sure that the fiber is taut between the holding fixtures and lower the second holding top. The fiber
should be held in line with the recoat mold channel.
7. Lower the recoat top gently, then lift the lifting lever to capture the fiber within the mold cavity.
It is important to keep the fiber taut between the holding fixtures to prevent the fiber from bowing at the recoat. It is
also important to avoid touching the exposed glass surface, as this could significantly lower the strength of the fiber.
Rev A, September 14, 2020
Recoat and Proof Test Components
Chapter 9: Recoat Process
Page 35