Zte Unitrans ZXMP M600 Technical Instructions page 69

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A.6 Channel Bandwidth
1.
2.
A.7 Insertion Loss
It is a parameter of a demultiplexer. A demultiplexer includes two kinds of
bandwidth: channel bandwidth @-0.5dB and channel bandwidth @-20dB. They
respectively indicate the change value of the corresponding working wavelength
when the insertion loss of the demultiplexer decreases for 0.5dB and 20dB.
Bandwidth @-0.5dB: It describes the band pass performance of the
demultiplexer. A good band pass performance curve should be even and broad.
The greater the bandwidth is, the better the performance.
Bandwidth @-20dB: It describes the stopband performance of the demultiplexer.
The stopband performance curve should be steep. The greater the bandwidth is,
the better the performance.
The central wavelengths of CWDM filter in the case of channel bandwidth
@-0.5dB end in "1". The channel interval is 20nm and the precision is ±6.5nm.
When ordinary optical fibers are used, the bandwidth of the wavelengths are
respectively 1471±6.5nm, 1491±6.5nm, 1511nm±6.5nm, 1531nm±6.5nm,
1551nm±6.5nm, 1571nm±6.5nm, 1591nm±6.5nm and 1611nm±6.5nm.
Insertion loss indicates the attenuation of the optical signals caused by the WDM
equipment. It directly affects the transmission distance of the WDM system.
It is the ratio between the optical power of the input port and that of the output
port in the equipment. The formula for calculating it is as below:
log
IL=-10 (Pi/Po)
In the formula, Pi indicates the optical power transmitted to the input pot, while
Po indicates the optical power received from the output port.
A-5
Appendix A Term Description