Handling Fiber and Fiber Optic Connectors
Network Interface (NI) Modules
page 5-30
OmniSwitch 7700/7800 Hardware Users Guide
April 2005
Handling Fiber and Fiber Optic Connectors
Using fiber is extremely simple, but several important standards should always be practiced. For best
results, you should:
•
Use premium grade jumper cables with duplex SC connectors
•
Keep your fiber optic connectors clean
•
Keep the transceiver interface clean
•
Attenuate properly
For detailed information on these recommendations, refer to the sections below.
Use Premium Grade Jumper Cables with Duplex SC Connectors
There are many brands of fiber optic jumper cables, with a wide range of quality between each manufac-
turer. Premium cables do three things well:
•
They provide a good polish on the fiber optic connector endface (where the light exits the cable).
Endface geometries must be exceptionally precise and aligned to extremely tight tolerances. The better
the endface geometry, the lower the loss and more consistent the connection. Poor connector interfaces
will reflect light back into the laser, causing an increase in laser noise.
•
They mate well with other connector interfaces. Chances are the manufacturer of the jumper cable will
not be the same as the manufacturer of the transceiver connector interface. Premium jumper cables
mechanically align themselves well into most transceiver interfaces. This provides both better perfor-
mance as well as better repeatability. You will always see a variance in transceiver power due to
connector alignment, often as much as 0.3 to 0.7 dB. Good jumper cables help reduce this variance.
•
They continue to mate well after many insertions and removals. Premium grade jumper use premium
connectors that maintain their mechanical integrity up to and beyond 2000 insertion cycles.
For better repeatability, always use duplex (two connectors fused together and terminated to two cables)
SC connectors on your jumper cables when connecting to a fiber-optic transceiver. Two simplex connec-
tors inserted into a transceiver interface will often have up to 3 dB greater variation in repeatability
compared to duplex connectors.
Never bend the fiber optic cable beyond its recommended minimum bend radius. This introduces bend
losses and reflections that will degrade the performance of your system. It can also damage the fiber,
although fiber is much tougher than most would assume. Still, it is highly recommended to buy only
jumper cables with 3mm Kevlar jacketing, which offer superior protection and longer life.
