9-22
Item
Single mode fiber
Multi-mode fiber
Light source and
transmission distance
Uses lasers as the light source often
within campus backbones for distance
of several thousand meters
Uses LEDs as the light source often within
LANs or distances of a couple hundred
meters within a campus network
Table9-6 Allowed maximum tensile force and crush load
Period of force
Tensile load (N)
Crush load (N/mm)
Short period
150
500
Long term
80
100
Fiber connectors are indispensable passive components in an optical fiber communication system.
They allow the removable connection between optical channels, which makes the optical system
debugging and maintenance more convenient. There are multiple types of fiber connectors.
Figure9-5 Appearance of an LC connector
Follow these guidelines when you connect an optical fiber:
•
Before connecting an optical fiber, make sure the connector and cable type match the interface
module.
•
The fiber Ethernet port of the firewall supports only the LC connector.
•
Fiber connectors are fitted with dust caps. Keep the dust caps secure when the fiber connectors
are in use. Install dust caps when the fiber connectors are not in use to avoid damage to their
end face. Replace the dust cap if it is loose or polluted.
•
Before connecting an optical fiber, use dust free paper and absolute alcohol to clean the end
face of the two fiber connectors. You can brush the end faces only in one direction.
•
Never bend or curve a fiber.
•
If the fiber has to pass through a metallic board hole or bend along the acute side of mechanical
parts, the fiber must wear jackets or cushions.
