A laser Light Pulse does not consist of a single frequency, it consists of several laser frequencies.
Since these different frequencies will reach the end of the fiber line at different times due to their different speeds, they cause dispersion. When the sign reaches the end of the fiber line, it spreads over time.
Chromatic distribution (CD) causes pulse expansion and can increase Bit Error Rate, which can have a very negative impact on transmission performance.
EXFO FTB-5800 CD Analyzer is the device that detects and analyzes these negative factors affecting the transmission performance in fiber optic lines.
Zero-Dispersion wavelength repeatabilty