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Optical Fiber Cable. Optical Fiber Classification. Can be classified in a number of ways On the basis of manufacturing Single component/Multi component Glass core glass clad Doped silica core clad All plastic fiber On the basis of profile Step index Multi mode Mono mode Graded index .
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Optical Fiber Cable www.bzupages.com
Optical Fiber Classification • Can be classified in a number of ways • On the basis of manufacturing • Single component/Multi component • Glass core glass clad • Doped silica core clad • All plastic fiber • On the basis of profile • Step index • Multi mode • Mono mode • Graded index www.bzupages.com
Multi Mode Step Index • Made up of glass or doped silica • Reasonably large core diameter and NA to facilitate efficient coupling of incoherent light • Performance characteristics vary widely depending upon material used in fabrication • Structure • Core diameter: 50 to 400 µm • Clad diameter: 125 to 500 µm • Buffer jacket diameter: 250 to 1000 µm • Numerical Aperture: 0.16 to 0.5 www.bzupages.com
Multi Mode Step Index • Performance characteristics • Attenuation • Approx 2.5 to 50 dB/Km @ 0.85 µm wavelength • 40 dB/Km for glass fiber • 5 dB/Km for doped silica fiber • 0.4 dB/Km @ 1.3 µm wavelength • Bandwidth • 6 to 50 M Hz Km • Application • Short haul communication • Limited bandwidth applications • Relatively low cost applications www.bzupages.com
Multi Mode Graded Index • Made up of glass or doped silica • Higher purity level than MMSI fibers • Many different structural profiles developed for different application • Structure (Typical) • Core diameter: 30 to 100 µm • Clad diameter: 100 to 150 µm • Buffer jacket diameter: 250 to 1000 µm • Numerical Aperture: 0.2 to 0.3 www.bzupages.com
Multi Mode Graded Index • Structural types • 50 /125 µm (core-clad) with NA between 0.20 to 0.24 recommended by ITU-T for telecom applications @ 0.85 and 1.3 µm wavelength. Now mainly used for Data Links and LANs • 65/124 µm (core-clad) with NA between 0.26 to 0.29 for long distance subscriber loops operating @ 0.85 and 1.3 µm. Now mainly used for LANs • 100/125 µm (core-clad)with NA of 0.29. High coupling efficiency with LEDs operating @ 0.85 µm. Used in low cost, short distance applications www.bzupages.com
Multi Mode Graded Index • Performance characteristics • Attenuation • Approx 2 to 10 dB/Km @ 0.85 µm wavelength • 0.4 dB/Km @ 1.3 µm and 0.25dB/Km @1.55 µm • Bandwidth • 300 to 3 GHz-Km • Application • Medium haul communication • Medium to high bandwidth applications www.bzupages.com
Single Mode Step Index • Made up of doped silica • Small core diameter • Structure • Core diameter: 5 to 10 µm • Clad diameter: Generally 125µm • Buffer jacket diameter: 250 to 1000 µm • Numerical Aperture: 0.08 to 0.15 (usually around 0.1) www.bzupages.com
Single Mode Step Index • Performance characteristics • Attenuation • Approx 2 to 5dB/Km @ 0.85 µm wavelength • Bandwidth • Greater than 500MHzKm • Theoretically 40GHzKm @ 0.85 µm • Practical bandwidth of 10GHzKM @ 1.3 µm • Application • Long haul communication • Excessive bandwidth applications www.bzupages.com
Plastic Clad Fibers • Multimode fibers with both step and graded profiles • Glass core and plastic clad (often silicon rubber) • Lower induced radiation losses (improved performance under certain environments) • Slightly cheaper • Structure SI GI • Core diameter: 100 to 500 50 to 100 µm • Clad diameter: 300 to 800 125 to 150 µm • Buffer jacket diameter: 500 to 1000 250 to 1000 µm • Numerical Aperture: 0.2 to 0.5 0.2 to 0.3 www.bzupages.com
Plastic Clad Fibers • Performance Characteristics • Step Index: 5 to 50 dB/Km • Graded index: 4 to 15 dB/Km www.bzupages.com
Optical Fiber Cable • Why we need cabling • Unprotected optical fiber has many disadvantages • Poor strength and stability • Brittle and small cross sections are susceptible to damage during laying • Hence cabling is done to improve • Fiber protection • Fiber damage and breakage during installation and throughout life www.bzupages.com
Optical Fiber Cable • Cable strength • Should have similar mechanical properties as of electrical cables • Increase in resistance to mechanical stress, strain and adverse environmental condition • Squeezing and vibrations • Identification of joints • Stability • Reduction of micro bending due to environmental conditions specially temperature • Reduction in hydrogen absorption and nuclear radiation exposure www.bzupages.com