N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 5 - SONET, WDM, DWDM and B-ISDN Technologies                                                                Slide 8 of 76 _________________                                                                                  __________

                                           Optical Fiber Composition

                                                    Core

                                                    Cladding

                                                    Sheath

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An optical fiber consists of three distinct parts: the core, the cladding and the sheath or jacket. The buffer material is used to protect the core and cladding from damage. The strength material surrounds the buffer material to prevent it from developing stretch problems

Core - The light-carrying element at the center of the optical cable. It is normally several times the wavelength of the light to be carried. It varies with Single-Mode or Multi-Mode wave propagation. 

Cladding - Cladding thickness is greater than the core radius. It is made of silica with controlled impurities

Sheath - Polyvinyl Chloride material is used for the jacket. The sheath is added to protect against abrasion, solvents and other contaminants.

                                A Typical Five-Fiber Optical Cable