This document provides information about optical fibers, including their core components, types, transmission characteristics, and applications. It discusses the basic structure of an optical fiber, which consists of a glass core surrounded by a cladding layer and protective coating. The document outlines the three main types of optical fibers - step-index multimode, graded-index multimode, and single mode - and their uses in different communication systems. It also covers optical fiber transmission windows, loss calculations, and system components.
10. protective coating
glass cladding
optical fiber core
Optical FiberOptical Fiber
An optical fiber is a thin (2 to 125µm), flexible medium capable of guiding an optical ray.
Preferable because of,
• Large bandwidth, light weight, and small diameter
• Nonconductivity (no EMI & RFI)
• Longer distance signal transmission with lesser attenuation
• Security & greater repeater spacing
• Designed for future applications needs
11. Optical FiberOptical Fiber
The basic question is
“how much information is to be sent and how far does it have
to go?”
Five basic categories of application have become important for
optical fiber:
• Long-haul trunks
• Metropolitan trunks
• Rural exchange trunks
• Subscriber loops
• Local area networks
12. Basic fiber optic communication systemBasic fiber optic communication system
13. Transmission WindowsTransmission Windows
• Optical fiber transmissions uses wavelengths in the near
infrared portion of the spectrum
• Both Lasers and LEDs are used to transmit light through fibers
• Lasers are used for 1310 nm or 1550 nm single mode
transmissions
• LEDs are used for 850- or 1300 nm multimode applications
18. Fiber Optic TypesFiber Optic Types
• Step-index multimode fiberStep-index multimode fiber
– the reflective walls of the fiber move the light pulses to
the receiver
• Graded-index multimode fiberGraded-index multimode fiber
– acts to refract the light toward the center of the fiber
by variations in the density
• Single mode fiberSingle mode fiber
– the light is guided down the center of an extremely
narrow core
Three basic types of optical fibers are used in communication
systems
21. Step-index multimode fiber has an index of refraction profile that “steps” from
low to high to low as measured from cladding to core to cladding.
Relatively large core diameter and numerical aperture characterize this fiber.
The core/cladding diameter of a typical multimode fiber used for
telecommunication is 62.5/125 μm (about the size of a human hair).
The term “multimode” refers to the fact that multiple modes or paths through
the fiber are possible.
Stepindex multimode fiber is used in applications that require high bandwidth
(< 1 GHz) over relatively short distances (< 3 km) such as a local area network or
a campus network backbone.
Step-index multimode fiber