Learning the Different Coating Stripping Methods

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The cladding
power stripper also referred to as the multimode optical power stripper
is designed for amplifier applications and high power fiber laser. It is an
ideal device for ASE, residual pump power stripping, core modes that have
escaped from double cladding fibers inner cladding while ensuring preservation
of single power minimal degradation and beam quality (M2). Single power that is
reflected into the inner cladding may also be stripped out too.  The handling capability of the stripping
power goes to 800W or at times may be even higher

 

Stripping the Coating

 

The fibers that most reputable companies supply
all come with a standard acrylate single layer coating or, in some such as the
high power products, a coating that is high temperature enduring. In comparison
to dual layer coatings, the coatings that are single layer are more brittle and
smooth. The coating can be removed readily using the conventional tools for
fiber stripping such as the Fitel S-210 Clauss or CFS-1 for 125 μm cladding
diameter fiber or for larger cladding diameters the Clauss No Nik stripper is
used. For fibers whose outer diameter is non-standard, it is recommended that
an adjustable stripper is used.  Thermal
strippers such as those that are attached to the Schleuniger FiberStrip 7030 or
the Vytran FFS-2000 can be used for all fiber in a safe way.

 

Alternatively, chemical stripping of fibers
can be done using an appropriate solvent. For example, the coating can be
exposed for one minute to sulfuric acid at 120°C sulfuric acid. Before the
fiber is dipped into the liquid, the tip should be sealed with a drop of glue
of 2 mm in diameter or through the end fiber hole collapsing using a fusion
splicer.  It is worth noting that most
glue types are dissolved in this acid, but epoxies that are two-component such
as the Epotek ND353 tends to dissolve in a slower manner than the coating.

 

It is also possible to obtain chemical
stripping through application on the fiber tip, of paint stripper. The paint
stripper is usually in the form of a gel so as to reduce the occurrence of
out-gassing and can be applied easily using a small brush. After a minute or
so, the coating becomes soft and is removed easily using a lens tissue. It is
worth noting that paint stripper typically contains dichloromethane (CH2Cl2)
and as such there may be restrictions by local regulations to use it. For lower
quality and faster stripping, another option would be to use a normal cigarette
lighter to burn the coating off. However, the fiber may end up becoming brittle
hence not the best choice for stripping.