N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 5 - SONET, WDM, DWDM and B-ISDN Technologies                                                             Slide 21 of 76 _________________                                                                                  __________

                                                        Optical System Bandwidth

                                                Modal Delay Spreading 

                                                Material Dispersion

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The limitation of the bandwidth in a fiber appears from modal delay spreading and Material dispersion.

Modal Delay Spreading -  Multi-mode propagation causes the light rays

Material Dispersion - This dispersion arises from the variation in the velocity of light through the fiber with the wavelength of light. This causes spreading of the pulses. This limits the modulation bandwidth. 1.3 and 1.5 mm wavelengths with certain fibers give much better modulation- bandwidth performance.