Specifications

RADring
Installation & Operation Manual Token Ring Desing Considerations
3/11/98 12:26 Fiber Optic Design Considerations 6-13
Losses in Optical Fibers
Typical losses that must be considered when calculating losses in actual fiber
optic links are as follows:
Cable Losses 3-5 dB/km
Connector Losses 1 - 2dB/connector
Splice Losses 0.1 - 0.3dB/splice
Aging, Temperature 3dB
The values given above are to be used as guidelines. Always use cable and
connector losses specified by the manufacturer.
Connectors are the weakest point. The "cost" of a "bad" connector may be as
high as 1 km of fiber.
Note
Do not design in too many connectors!
Connector losses decrease as fiber diameter increases.
Example: Optical link (ring segment) with 3 km of 100/140 micron fiber.
Cable Loss 3 X 4.5dB/km = 13.5dB
Connector Loss 2 X 1.5dB = 3.0dB
Total Losses 16.5 dB
Link Budget 18dB
Link Margin (aging,
splices)
1.5dB
The link margin indicates the reserve for unexpected increases in link
attenuation, such as splices, increased attenuation due to fiber aging, or
decreased transmit power due to component aging.