Fiber Optic Cable diagram: Overview, Questions, Preparation

An optical fiber is a thin, transparent fiber used for transmitting data in the form of light impulses. It has a higher bandwidth than other cables and is used in telecommunication services.

Optical fiber has three layers:

• Core: It forms the center of the fiber, and is made of thin glass.
• Cladding: The cladding surrounds the inner core and helps the light to reflect.
• Buffer coating: It is a coating present on the outside of the fiber. It helps to prevent it from any external damage.

The different types of optical fibers are as follows:

• Based on the distance of propagation of light

Single-mode fibers: They are used for longer distances. 

Multi-mode fibers: They are used for shorter distances. 

• Based on the refractive index 

Step-index fibers: These fibers have a cladding that has a uniform refractive index.

Graded-index fibers: In these fibers, the refractive index decreases as the distance from the fiber axis increases.

• Based on the materials used

Plastic optical fibers: The core material used is made up of polymethylmethacrylate for transmitting light.

Glass fibers: The fibers used are made up of extremely thin glass material.

The optical fiber uses light impulses to transmit a huge amount of data from one point to another. The light rays bounce from the fiber walls and travel through them.

The various components of a fiber optic cable are:

• Transmitter: It transmits the light signals from one point to another.
• Optical fiber: It acts as the medium for transmitting the impulses.
• Receiver: It decodes the light impulses received from the transmitter. 
• Regenerator: It helps to regenerate the impulses for long-distance data transmissions. 

The advantages of using an optical fiber are:

• Higher speed: The optical fiber can carry and transmit a large amount of data in a short period.
• Cheap: The materials used to manufacture the optical fiber are far cheaper than wires made from copper or other metals.
• Light-weight: Optical fibers have a smaller diameter than copper wires and are very light-weight.
• Less signal degradation: in optical fibers, the loss of electrical signals is less, and they do not interfere with other signals in the cable.

The limitations of using an optical fiber are as follows:

• Less power: The sources used for emitting light have a low power supply. Even though a power supply can be added to improve it, it will lead to an extra cost.
• Fragility: Optical fibers are fragile and can be damaged easily.
• Application: Optical fibers can only be used on the ground and have limited applications.

In class 12, the chapter optics describes various phenomena like reflection, dispersion, and refraction of light.

It further describes the construction and working of different optical instruments like telescopes, fiber optics, and the human eye.

This chapter carries a weightage of 18 marks in the exam. Hence, one or two questions on fiber optics may be asked.

Q: Who discovered optical fibers?

Q: The fiber optic cable follows which principle?

Q: Why is silica used for the fabrication of fiber optic cables?

Q: What is the maximum speed recorded for optical fiber?

Q: What is the transmission bandwidth for fiber optics?

Q: Can we send both analog and digital signals through fiber optics?