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Cisco ONS 15540 ESPx Hardware Installation Guide
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Chapter 3 Connecting the Cisco ONS 15540 ESPx
Cleaning the Shelf and Connectors
Fiber optic connectors are used to connect two fibers together. When these
connectors are used in a communication 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
not repeatable or inaccurate communication.
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. Therefore, the connector must be
precisely aligned and the connector interface must be absolutely free of trapped
foreign material.
Connector, or insertion, loss is a critical performance characteristic of a fiber
optic connector. Return loss is also an important factor. It specifies the amount of
reflected light; the lower the reflection the better the connection. The best
physical contact connectors have return losses better than –40 dB, although –20
to –30 dB is more common.
Note
MU terminators are shipped with the system. These are used to terminate the pass
through ports of the OADM that are not used. For instance, the pass through in
must be terminated if it is unused, otherwise the return loss at Trunk IN will be
unacceptably high.
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 cover
installed when not in use.
Before installing any type of cable or connector, refer to Cisco ONS 15540 ESPx
Cleaning Procedures for Fiber Optic Connections or go to:
http://www.cisco.com/univercd/cc/td/doc/product/mels/15540x/15467kit.htm
When cleaning fiber components, procedures must be followed precisely and
carefully with the goal of eliminating any dust or contamination. A clean component
connects properly; a dirty component may transfer contamination to the connector, or
it may even damage the optical contacts. Inspecting, cleaning, and re-inspecting are
critical steps that must be done before making any fiber connection.
