Dust cap
6
Housing assembly
3
Cleaning the Fiber-Optic Connectors
Fiber-optic connectors are used to connect two fibers together. When these connectors are used in a
communications system, proper connection becomes a critical factor.
Fiber-optic cable connectors can be damaged by improper cleaning and connection procedures. Dirty or
damaged fiber-optic connectors can result in communication that is not repeatable or is inaccurate.
Fiber-optic connectors differ from electrical or microwave connectors. In a fiber-optic system, light is
transmitted through an extremely small fiber core. Because fiber cores are often 62.5 microns or less in
diameter, and dust particles range from a tenth of a micron to several microns in diameter, dust and any
contamination at the end of the fiber core can degrade the performance of the connector interface where the
two cores meet. The connector must be precisely aligned, and the connector interface must be absolutely free
of trapped foreign material.
Connector loss or insertion loss is a critical performance characteristic of a fiber-optic connector. Return loss
is also an important factor. Return loss specifies the amount of reflected light; the lower the reflection, the
better the connection. The best physical contact connectors have return losses greater than -40 dB, although
-20 to -30 dB is more common.
The connection quality depends on two factors: the type of connector and the proper cleaning and connection
techniques. Dirty fiber connectors are a common source of light loss. Keep the connectors clean at all times,
and keep the dust covers installed when the connectors are not in use.
Before installing any type of cable or connector, use a lint-free alcohol pad from a cleaning kit to clean the
ferrule, the protective white tube around the fiber, and the end-face surface of the fiber.
As a general rule, whenever there is a significant, unexplained loss of light, clean the connectors.
Guidelines
The connectors used inside the system are cleaned by the manufacturer and connected to the adapters in a
proper manner. The operation of the system should be error free if the customer provides clean connectors
on the application side and follows these guidelines:
•
Cleans the connectors using either a CLETOP cassette cleaner (Type A for SC connectors and Type B
for MT-RJ connectors) or lens tissues before connecting to the adapters; uses pure alcohol to remove
contamination.
•
Does not clean the inside of the connector adapters.
•
Does not use force or quick movements when connecting the fiber-optic connectors in the adapters.
•
Covers the connectors and adapters to keep the inside of the adapters or the surface of the connectors
from getting dirty when not using the connectors or while cleaning the chassis.
Cisco Catalyst 6807-XL Switch Hardware Installation Guide
OL-30656-01
87
Transceivers, Module Connectors, and Cable Specifications
Cleaning the Fiber-Optic Connectors
