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Appendix.2 General precautions in handling optical fiber cables
You might break the fibers of optical fiber cables if you handle the cables in the same way as conventional
cables. To prevent this, observe the following precautions.
(1) Do not bend the cables excessively.
The bending radius must be more than 10 times the outer diameter during installation; otherwise, the
optical loss would increase and fibers break.
(2) Do not squeeze the cables.
Squeezing the cables damages the outer sheath and break the fibers, be very careful about doors and
equipment edges.
(3) Do not twist the cables.
Do not give one meter of cabling more than one twist in installation as this might increase the optical loss
and break the fibers.
(4) Do not pull on the optical connectors when installing the cables.
The cables are built around the optical connectors. These connectors are precision equipment which is
prone to damage due to external shock and tension stress.
(5) Do not pull on the cables with excessive force.
The allowable tension stress depends on the type of cable. Check the stress limits before installation, and
install the cables with tension stress below the limit.
(6) Do not place heavy things on the cables.
Do not place heavy things on the cables (do not step on tem ) as this might increase the optical loss and
break the fibers.
About the details of installation points, please refer to the following instructions which OpNext
Japan, Inc. publishes.
- Optical fiber cable installation guide
- Optical fiber cable installation procedure
- CA7103 Cable assembly specification
- Optical connector assembly tools CT7001 Assembly guide
Appendix.3 The method to measure the optical loss level.
(1) About the level of transmission optical power and loss of the optical fiber
The allowable value of the optical loss of the optical cable is calculated with the following equation.
The allowable value of the optical loss = The allowable value of the optical loss of the optical cable
The optical sending level of sending LED on the sending side.
The optical receiving level of receiving photo on the sending side.
The room level when the light source of sending LED became a half. ---
If the loss of the optical cable is within 12(dBm), it can be judged that it is good from the above equation.
(2) How to measure the optical loss of the optical cable by the optical meter
[1] The measurement wavelength of the optical meter is fitted to the sending light source wavelength.
( Example ) Optical meter
"dBm", "850 nm" are set up with the optical switch. (The "x" part of the Fig A.1.)
- Optical sending level - Optical receiving level - room level
= (-17 ) - (-32 ) - 3
= 12 ( dBm )
Maker : SOAR
Type
: MODEL 1805
Light source wavelength --- 850 nm range
A - 3
Appendix Optical Cable
--- -17 dBm
--- -32 dBm
3 dBm
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