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

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

Multi Mode Step Index Performance characteristics Attenuation Approx 2.5 to µm wavelength 40 dB/Km for glass fiber 5 dB/Km for doped silica fiber µm wavelength Bandwidth 6 to 50 M Hz Km Application Short haul communication Limited bandwidth applications Relatively low cost applications

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

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 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 0.85 and 1.3 µm. Now mainly used for LANs 100/125 µm (core-clad)with NA of High coupling efficiency with LEDs 0.85 µm. Used in low cost, short distance applications

Multi Mode Graded Index Performance characteristics Attenuation Approx 2 to µm wavelength µm and µm Bandwidth 300 to 3 GHz-Km Application Medium haul communication Medium to high bandwidth applications

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)

Single Mode Step Index Performance characteristics Attenuation Approx 2 to 0.85 µm wavelength Bandwidth Greater than 500MHzKm Theoretically 0.85 µm Practical bandwidth of 1.3 µm Application Long haul communication Excessive bandwidth applications

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 StructureSIGI Core diameter: 100 to to 100 µm Clad diameter: 300 to to 150 µm Buffer jacket diameter: 500 to to 1000 µm Numerical Aperture: 0.2 to to 0.3

Plastic Clad Fibers Performance Characteristics Step Index:5 to 50 dB/Km Graded index:4 to 15 dB/Km

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

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