190 likes | 462 Views
Optical communication Part –1 . Where:. =. And n 2 > n 1. i. e. r. i. t. t. e. i. i. r. Reflected ray. Impinging ray of monochromatic light. Second order reflected ray. n 1. Optically transparent plate of n 2 with parallel surfaces in a medium with n 1 (n vacuum =1).
E N D
Optical communication Part –1
Where: = And n2 > n1 i e r i t t e i i r Reflected ray Impinging ray of monochromatic light Second order reflected ray n1 Optically transparent plate of n2 with parallel surfaces in a medium with n1 (nvacuum =1) Refracted ray n2 n1 Where: = angle of incident ray = angle of reflected ray = angle of refracted ray = angle of emerging ray Emerging ray
2 2 No refraction; ( = 900) 900 n1 n1 n2 > n1 n2 n2 > n1 n2 i Refraction; ( < 900)
n1 n2 n3 n4 n5 n6 n7 Where: n1 > n2 > n3 > n4 > n5 > n6 > n7 > n8
1 2 1 J K N 2 = angle of deflection n1 Composite beam + …+ Prism n2 Base of prism n2> n1
Impinging circularly or elliptically polarized ray Reflected linearly polarized ray Birefringent medium Two refracted linearly polarized rays
Absorption Scattering Impurities Rays of light
Attention due to - OH 1.6 1.2 1.4 ( m) Transmitted optical loss (dB)
Preasure Streching points Fiber R Compression points R = radius of bent
Plastic KavlerTM Buffer coating Cladding Glassy core Cross section (not to scale)
n (x) n1 Step index profile n2 x Core fiber n (x) Coating n1 Graded index profile x
d = 8.6-9.5 m D = 125 2 m D = 125 2 m d = 50 m Core fiber ncore nclad Cladding Cladding nclad Multimode fiber - many rays (modes) may propagate Single mode fiber -one ray (mode) due to small ratio D/d propagates
Graded index n2 n1 Step index
Critical cone Cladding n2 n1 crit Core n1>n2
1 1 t t Cladding n2 n1 Ray B Ray A Core Impulse entering the fiber Impulse exiting the fiber
2 1 t t Cladding n2 n1 t1 t2 Core Impulse entering the fiber Impulse exiting the fiber
Material dispersion Wavelength dispersion Dispersion flattened Conventional fiber 20 Zero-dispersion points Dispersion flattened Dispersion, psec/nm-km Conventional fiber Dispersion-shifted fiber -20 Dispersion-shifted fiber 1200 1400 1600