2. 3 Fiber-Optic Cable

3. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives  Explain how fiber-optic cable is used to transmit data.  Summarize the advantages of fiber-optic cable compared with copper core cable.  Explain the properties of light.  Compare multimode and single-mode fiber-optic cable.

4. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives  Recall the characteristics and specifications of the IEEE 802.3 fiber-optic standards.  Recall the characteristics and specifications of the FDDI standard.  Give examples of the problems associated with fiber-optic cable splices.  Identify common fiber-optic cable test instruments and summarize how they are used.

5. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable  Consists of a glass or plastic core  Carries pulses of light

6. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Characteristics of Fiber-Optic Cable  Provides for data security  Immune to electromagnetic interference  Lightweight and small in diameter  Safety  Wide bandwidth  Corrosion- and water-resistant  Supports data transmission over longer distances than copper core cable

7. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. The Nature of Light  Form of energy  Classified as electromagnetic waveelectromagnetic wave  Identified in the electromagnetic wave spectrum chart  Light wave pattern is described using the term wavelength wavelength

8. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Electromagnetic Wave Spectrum

9. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Construction  Composed of glass or plastic core surrounded by cladding  Classified as loose tube or tight buffer  National Electrical Code (NEC) is referred to for building specifications or standards

10. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Attenuation in Fiber-Optic Cable Transmission  Scattering—No light is 100% pure, hence scattering Scattering  Dispersion—Main factor in limiting length of fiber- optic cable; longer cable means more dispersion Dispersion  Extrinsic losses—Main reasons for signal loss Extrinsic losses  Fresnel reflection loss—Minimized by sealing material Fresnel reflection loss

11. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Specifications  Multimode Fiber-Optic Cable Multimode Fiber-Optic Cable  Single-Mode Fiber- Optic Cable Single-Mode Fiber- Optic Cable

12. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Specifications (Cont.)  Graded-index multimode fiber-optic cable Graded-index multimode fiber-optic cable  Step-index multimode fiber-optic cable Step-index multimode fiber-optic cable

13. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. IEEE 802.3 Standards

14. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. IEEE 802.3 Standards (Cont.)

15. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. The media converter in the illustration converts 10/100 Mbps UTP to 100 Mbps fiber-optic. What IEEE standard is most likely used for the 100 Mbps fiber-optic connection? Applied Networking

16. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber Distributed Data Interface (FDDI)  Constructed as a pair of rings  Uses token passing media access method  Guarantees continuous communication  If one ring fails, the other ring automatically provides path for communication

17. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. FDDI Fault Tolerance

18. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Connectors Fiber-Optic Cable ConnectorDescription STRound. Uses a push and twist connection SCSquare. Uses retaining clips FCRound. Uses screw threads LC (single)Square. Small form factor. LC (duplex)Two single LC connectors held together with a clip MTRJIncorporates two fiber-optic cores into one assembly

19. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Connectors (Cont.)

20. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Installing Fiber-Optic Cable Connectors  Slices, couplings, and connections require special equipment and techniques  To cut glass core fiber-optic cable:  Scribe the core with a sharp, cleaving tool  Apply pressure to the scribed area  Plastic core fiber-optic cable is cut with a sharp cutting tool—it is not cleaved

21. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fusion Splice  Before splicing, the outer sheath must be removed from cable end  Splice area must be clean, to avoid signal loss  End of the fiber-optic core is cleaved, not cut through  Two ends of fiber core are aligned, melted together, covered, and crimped

22. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Fiber-Optic Cable Meters  Power meter and light source—Most commonly used meter for testing short runs in cable  Used to calculate short runs and power loss  Optical Time Domain Reflectometer (OTDR) Optical Time Domain Reflectometer (OTDR)  Measures and records the effects of attenuation  Can measure cable length, locate breaks, and find faults in the cable and at its connections

23. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.  Dispersion  The distortion of the light wave pattern as it reflects off the core cladding.  Electromagnetic wave  A form of energy that behaves like a wave and can travel through a vacuum.  Extrinsic losses  Signal losses caused by physical factors outside the normal core, such as splices, connectors, and bends in the fiber core. Glossary

24. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.  Fiber Distributed Data Interface (FDDI)  A standard developed by ANSI that employs fiber- optic cable that can reach distances as far as 40 kilometers in length and support data speeds of 100 Mbps or higher. It is used mainly as a backbone for large network systems such as a MAN or a WAN.  Fresnel reflection loss  A type of signal loss that commonly occurs at connection points in fiber-optic cabling and is due to refraction property differences in the core material, the connector materials used for sealing the connector, and air. Glossary

25. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.  Fusion splice  Joining two fiber-optic cores using heat to fuse the materials together.  Graded-index multimode fiber-optic cable  A type of multimode fiber-optic cable that has a varying grade of core material. It is designed for maximum light conduction at the center of the core and gradually diminished light conduction toward the cladding.  Multimode fiber-optic cable  A type of fiber-optic cable that has a large core diameter and is susceptible to attenuation due to dispersion. Glossary

26. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.  Optical Time Domain Reflectometer (OTDR)  A meter for testing and troubleshooting long runs of fiber-optic cable. The OTDR conducts measurements based on the principle of attenuation.  Scattering  The loss of signal strength due to impurities in the core material.  Single-mode fiber-optic cable  A type of fiber-optic cable that has a small core diameter and limited dispersion. It can carry light farther than multimode fiber-optic cable. Glossary

27. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.  Step-index multimode fiber-optic cable  A general multimode fiber-optic cable that does not counter dispersion.  Wavelength  The total distance an electromagnetic or light wave travels during one full cycle. Glossary