Zte Unitrans ZXMP M600 Technical Instructions page 73

...................
A.13 Maximum -20dB Bandwidth
A.14 Dispersion Tolerance
Maximum -20dB bandwidth is a parameter of a Single Longitudinal Mode
(SLM) laser, the unit being nm. It indicates the optical bandwidth when the peak
wavelength decreases for 20dB
Dispersion is a transmission property of optical fibers. As optical pulses with
different wavelengths are transmitted at different rates over an optical fiber, the
dispersion shows the expansion of the optical pulse when transmitted over
optical fibers.
Pulse expansion will cause overlapping of the pulse codes transmitted through
digital communication over optical fibers, that is, inter-code interference will
occur. This will result in bit errors. To avoid bit errors, the pulse interval must be
extended, which will lower the transmission rate and consequently reduce the
communication capacity. On the other hand, the pulse expansion will become
increasingly serious with the increase of the transmission distance.
As the optical parts of the WDM system will be greatly affected by the
dispersion, there is a maximum dispersion value that the WDM system can
tolerate. This is called dispersion tolerance. The system can implement normal
transmission only when the dispersion tolerance is not exceeded.
A-9
Appendix A Term Description