NKT Photonics SuperK CONNECT, Руководство по эксплуатации продукта, Страница: 32 / 40

PM Fibers and keying
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diverging field. The wide divergence means that a standard butt joint cannot be
used with subsequent fiber delivery systems due to the coupling loss. Therefore
PCF is only suitable when the FD is fitted with an output collimator which can
adequately refocus the light with its achromatic lens. Put another way, if a PCF
fiber is butt coupled facet to facet using an FC/APC connector to another fiber,
the light delivery will essentially fail due to the scattering at the fused PCF end.
PM Fibers and keying
Fibers are keyed by measuring the Polarization Extinction Ratio (PER) to find both
the slow and fast axis of the fiber. The fiber key location is determined by the fast
axis.
Key alignment
For PM Fiber Delivery, the output key on the FD has been actively aligned to the
true fast axis of the fiber. The slow axis is close to parallel with the stress rod
structure (e.g. PANDA structure) and the fast axis is close to perpendicular with
the stress rod structure. On a non-PM fiber the key is not aligned but arbitrarily
set. The key on the input coupler is aligned correspondingly with the key on the
output connector.
Fiber and connector care
The fiber and its connectors are inspected and sealed in a clean environment
before shipping. For optimum system performance, follow the guidance below:
•
Avoid removing the connector or collimator/coupler caps when the FD is not
in used and stored.
•
When connecting the FD, avoid:
•
Excessive strain on the fiber through stretching or twisting.
•
Fiber bend diameters < 10 cm
•
Exposing the fiber and its facets to contaminants.
•
Take good care and handle the FD gently to prevent damage to the fiber or
its facets.
•
Before using the FD, inspect the fiber and its facets for damage and
contaminants - if they need cleaning see .
“Cleaning of fiber facets” on
page 33 .
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