What is Chromatic Dispersion?
All forms of dispersion degrade a light wave signal, reducing the data carrying capacity through pulse-broadening. Chromatic dispersion results from a variation in propagation delay with wavelength, and is affected by fibre materials and dimensions. Chromatic dispersion is a broadening of the input signal as it travels down the length of the fibre. The concept to consider when talking about chromatic dispersion (CD) should be optical phase. It is important to mention optical phase before any explanations of CD or group delay because of their mathematical relationship. Group delay is defined as the first derivative of optical phase with respect to optical frequency. Chromatic dispersion is the second derivative of optical phase with respect to optical frequency. Both of these phenomena occur because all optical signals have a finite spectral width, and different spectral components will propagate at different speeds along the length of the fibre. One cause of this velocity difference is
