How is the dispersion characteristic of a signal propagating in an optical fiber?

Update:25 May 2019

It can be described by three physical quantities: pulse broadening, bandwidth of the fiber, and dispersion coefficient of the fiber.
What is the cutoff wavelength?
It refers to the shortest wavelength of the fiber that can only conduct the fundamental mode. For a single mode fiber, the cutoff wavelength must be shorter than the wavelength of the conducted light.