02 optical fiber-waveguides
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Transcript of 02 optical fiber-waveguides
Optical Fiber Waveguides
SYED AHSAN RAZA
Overview of ContentsIntroduction
Ray Theory Transmission
Electromagnetic Mode Theory for Optical Propagation
Cylindrical Fiber
Single Mode Fibers
Introduction-Optical WaveguidesPhysical structure that guides electromagnetic waves in
optical spectrum
Optical Fibers
Rectangular Waveguides
Introduction-Classification of Optical Waveguides
Classification by GeometryPlanarStrip
Classification by Mode StructureSingle ModeMulti Mode
Classification by Refractive Index DistributionStep IndexGradient Index
Purification of Materials in Optical Fiber
Proposals by Kao and Hockham in 1966 to utilize Optical Fiber as communication medium (Loss>1000 dB/km)
Conventional glass refining techniques used to bring optical fibers losses down to 4.2 dB/km
Further research in glass refining processes allowed fiber manufacturing with losses below 1dB/km(Operation in 0.8-0.9 μm)
Reduced signal dispersion and lower losses found in operation at longer wavelengths (1.1-1.6 μm)
At 1.55 μm high performance fibers exhibited losses to the tune of 0.2 dB/km
Total Internal Reflection
Total Internal Reflection
Snell’s Law of Refraction
Transmission of light in Optical Fiber
Acceptance Angle
Maximum angle to the axis at which light may enter the fiber in order to be propagated
For a fiber with regular cross section, an incident meridional ray greater than the critical angle will continue to be reflected and transmitted inside the fiber
Acceptance Angle
Numerical ApertureProvides the relationship between
CoreCladdingAir
Numerical Aperture
Numerical Aperture
Numerical Aperture