Fiber Optic Cables: Types, Signal Loss, and Manufacturing
Fiber Optic Classifications
Dielectric Materials: Silicon, Multicomponent Glass, Plastic
Propagation Modes: Single-mode (SM), Multimode
Refractive Index Distribution: Step Index (SI), Gradual Index (GI)
Signal Losses in Fiber Optics
Absorption Losses: Light converts to heat within the fiber.
Rayleigh Scattering Losses: Light scattering due to particles.
Non-Uniform Structure Scattering: Light dispersion from core-cladding irregularities.
Bending Losses: Light escapes due to fiber bends.
Microcurvature Losses: Increased loss from non-uniform pressure.
Joint Losses: Imperfections in connectors or splices cause light leakage.
Coupling Losses: Mismatches between fiber and transmitters/receivers.
Light Dispersion in Optical Fibers
Dispersion widens transmitted pulses due to varying travel times.
Modal Dispersion
Different propagation paths in multimode fibers cause pulse broadening.
Chromatic Dispersion
Wavelength-dependent dispersion.
Waveguide Dispersion
Dispersion due to slight core-cladding refractive index differences.
Fiber Optic Manufacturing
Chemical Vapor Deposition (CVD): Early method for low-loss fibers. Modified CVD (MCVD) is commonly used.
Double Crucible Method: Another fiber production technique.
Optical Sources
Laser Diodes (LD) and Light Emitting Diodes (LED) are used for signal modulation. Lasers suit high bandwidth, long links; LEDs are for shorter distances.
Optical Amplifiers
Optical amplifiers boost signal gain, extending transmission distances and improving network performance.