OPTICAL FIBERS

Agenda: Introduction Working Types Applications Advantages Disadvantages References

Introduction: Optical fibers are long, thin strands of very pure glass usually 120 µm in diameter. They are arranged in bundles called optical cables and used to transmit light signals over long distances.

Parts of Optical Fiber Core – thin glass center of the fiber where light travels. Cladding – outer optical material surrounding the core. Buffer Coating – plastic coating that protects the fiber.

Transmission of Light Through Optical Fibers Total Internal Reflection

The angle of the light is always greater than the critical angle. Cladding does not absorb any light from the core. The extent that the signal degrades depends upon the purity of the glass and the wavelength of the transmitted light.

Fiber Optics Systems has Optical Receiver Optical Regenerator Optical Fiber Transmitter

Types of Optical Fibers Optical fibers come in two types: Single-mode fibers Multi-mode fibers

Single-mode fibers Single-mode fibers are used to transmit one signal per fiber (used in telephone and cable TV). They have small core (9 microns in diameter) and transmit infra-red light from laser.

Multi-mode fibers Multi-mode fibers are used to transmit many signals per fiber (used in computer networks). They have larger cores (62.5 microns in diameter) and transmit infra-red light from LED.

Wavelength Division Multiplexing Signals with different wavelengths are combined, transmitted together, and separated again.

Time Division Multiplexing Several optical signals are combined, transmitted together, and separated again based on different arrival times.

Applications Carry plain old telephone service (POTS) For transmission of data Transmitting broadband signals In the biomedical industry Non-Communication Applications (sensors etc…)

Advantages Less Expensive Thinner High Carrying Capacity Less Signal Degradation Light Signals Low Power Digital signals Light Weight

Disadvantages Fiber optics are that the cables are expensive to install. The termination of a fiber optic cable is complex and requires special tools. They are more fragile than coaxial cable.

References Thank you