Sagem 4450E - Manual (Page 136)

CHAPTER 8
3P@C Installation Manual
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8. 8. 8. 8. Port
Maintenance
8.1. Checking the Optical Interface
Before connecting the optical interfaces at the transmitting end and at the receiving end through optical fibers,
you need to check and test the optical interface to avoid data transmission error and component damage.
1. Check whether the types of the optical interfaces at the transmitting and receiving ends match each other
The type of the optical interface at the transmitting end must match that at the receiving end in the respects:
Wavelength, optical fiber mode, transmission rate, and maximum transmission distance.
2. Check whether the type of the optical interface matches the type of the connected optical fiber
The type of the optical interface must match the type of the connected optical fiber in the respects: Wavelength,
optical fiber mode, and connector.
3. Check the optical interface for short-distance optical fiber transmission
For short-distance optical fiber transmission, you can use the self-loop method to check the optical
interface status. Connect the transmitting end with the receiving end of the optical interface through an
well-matched optical jumper. If the LINK indicator is on, it indicates that the transceiving function of the
optical interface is normal.
4. Check the optical interface for long-distance optical fiber transmission
When using the optical module supporting the long-distance transmission of more than 10 km, you need to
measure the optical power at the receiving end with an optical power meter, and ensure that the measured value
ranges between the overload point and receiving sensitivity.
„ If the optical signal power at the receiving end exceeds the overload point at the receiving
end, the optical interface at the receiving end will be damaged. Therefore, you need to use an
optical attenuator (active) or flange (passive) in the line to reduce the optical signal power at
the receiving end. You can adjust the attenuation value of the optical attenuator or flange, so
that the optical signal power at the receiving end is within a reasonable range.
„ If the optical signal power at the opposite end is less than the receiving sensitivity of the
optical interface at the receiving end, it will cause data loss. If this problem occurs, you need to
check whether the fiber connector contacts well or the optical interface is dirtied or damaged.
If the problem still occurs, it may be caused by poor fiber link transmission and extreme
transmission distance. Then, you need to consider using an optical amplifier or optical module
supporting longer distance transmission.
The table below describes the attributes of different types of optical modules, and the range of receiving optical
power.