Flashcards
Lasers and Optoelectronics
Cards in this deck (11)
- 1Waveguide MaterialsSilica
Silicon
Inp, GaAs
Lithium Niobate
Polymer. - 2Advantages of Optical Technology*High data rate, low transmission loss, and low bit error rates.
*Immunity from EM Interference
*Bi directional Signal Transmission
*High temperature capability.
*High reliability.
*Electrical Isolation.
*Signal security.
*Small (Typically μ10m), light weight, stronger. - 3Applications of Optical fibres.*Optical Communication systems.
*Non-communication applications:
*Sensors (Pressure, Temperature, Strain).
*Illumination.
*Imaging and Inspection.
*Medical applications, etc. - 4What is an optical fiber?An optical fibre is a strand of di-electric material- trapping radiation on one side and guiding it to the other.
n= c/v
n-Refractive Index
c-speed of light in vacuum
v= velocity of light in the medium.
Light travels more slowly the higher the value of n. - 5Schematic for Optical fibers.*Higher Refractive Index core
*Cladding with lower refractive index.
*Jacket for protection. - 6What is total internal reflection?When light is travelling from an area of high (optically dense medium) to low density medium, and the angle of incidence is greater than the critical angle.
- 7Step Index Optical Fibre.*Constant refractive index core, whatever the radial position and constant RI in cladding.
*Light guiding is due to TIR, both core and cladding made with silica. (RI variations induced by doping) - 8Optical Fibre Characteristics.*Refractive Index – Core high n, Cladding *Diameter of fibres – CORE: 5 μm (Single mode) to 125+ μm (multimode) – CLADDING: 50 μm to 1000+ μm
*Three types of fibre commonly used – Single mode, multimode & graded index - 9FabricationCore Index should be larger than Cladding index. Index difference generally really low.
- 10What is the rod-in-tube glass fibres fabrication process:– Insert a rod of high-index glass(core) into a tube with lower index (cladding)
– Heat to melt tube onto rod to form a thicker solid rod (preform)
– Heat one end of preform and draw to form a filament - 11Applications:
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- Flashcards on Lasers and Optoelectronics, created by Kemi Biye-Malcolm on 04/01/2017.
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- Kemi Biye-Malcolm
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