Describe in short about optical fiber

 

Describe in short about optical fiber.

Answer: An optical fiber is a flexible, transparent strand of very pure glass that acts as a light pipe to transmit light between two ends of the fiber. Optical fibers have a core surrounded by a cladding layer made of dielectric material. The optical signals in the core are confined by establishing a refractive index that is greater than the cladding.

Advantage of optical fiber:-

1.      High bandwidth over long distance
2.      Low transmission loss
3.      High information carrying capacity
4.      Small size and weight

Disadvantage of optical fiber:-

1.       Installation cost is high
2.       High possibility of physical damage
3.       Electronic power cannot be carried

What is Optical Fiber?

Optical fiber is a technology commonly associated with transomics, which is made of plastic or glass using lightweight pulses that travel along long fibers. Metal wires are preferred for transmission in optical fiber communication as the signals travel with low losses. Optical fibers are also not affected by electromagnetic interference. Fiber optical cable uses the application of the overall internal reflection of light. The fibers are designed to allow light to diffuse along with the optical fiber depending on the energy requirement and the transmission distance. Single-mode fiber is used for long-distance transmission, while multimode fiber is used for short distances. The outer cladding of these fibers requires better protection than metal wires.

Types of optical fibers

The types of optical fibers depend on the refractive index, the materials used and the propagation mechanism of the light.

The classification based on the refractive index is as follows:

Step index fibers: It has a core around the cladding that has a single uniform index of refraction.

Graded Index Fibers: The refractive index of optical fiber decreases as the radial distance from the fiber axis increases.

The classification based on the materials used is as follows:

Plastic Optical Fibers: Polymethyl methacrylate is used as a main material for light transmission.

Glass Fibers: It contains a lot of glass fibers.

The classification based on the mode of light propagation is as follows:

Single-mode fibers: These fibers are used for long distance transmission of signals.

Multimode fibers: These fibers are used for short-distance transmission of signals.

The core's propagation and refractive index are used to form four combinations of optical fibers as follows:

Phase index-single mode fibers

Graded Index-Single Mode Fibers

Phase index-multimode fibers

Graded Index-Multimode Fibers

How does optical fiber work?

Optical fiber works on the principle of total internal reflection. Light rays can be used to transmit large amounts of data, but there is a problem here - light rays travel in straight lines. So if we do not have long straight wire without any bends, using this utility is very labor intensive. Instead, optical cables are designed to bend all light rays inwards (using TIR). Light rays travel continuously, bounce off optical fiber walls and transmit end-to-end data. Although light signals deteriorate over increasing distances, the damage is very small compared to the use of metal cables, depending on the purity of the material used. The fiber optic relay system consists of the following components:

Transmitter - It generates light signals and encodes them to transmit.

Optical fiber - a medium that transmits a light pulse (signal).

Optical receiver - It receives the transmitted light pulse (signal) and decodes them as appropriate for use.

Optical Regenerator - required for long distance data transmission.

Advantages of optical fiber communication

Financial and costly

Thin and flammable

Low power consumption

Low signal attenuation

Comfortable and lightweight

How fiber optics works

Fiber optics pulse data - or photons - in the form of light particles through a fiber optic cable. The glass fiber core and cladding each have a different refractive index, which bends the incoming light at a certain angle. When light signals are transmitted through a fiber optic cable, they reflect the core and cladding in a series of zig-zag bounces, adhering to a process called total internal reflection. Light signals do not travel at the speed of light due to the dense glass layers, but instead travel at 30% slower than the speed of light. In order to restore or amplify the signal throughout its journey, fiber optics transmitters sometimes need repeaters over long distances to convert the optical signal into an electrical signal, processing the electrical signal and reproducing the optical signal.

Fiber optic cables support up to 10-Gbps signals. In general, as the bandwidth capacity of a fiber optic cable increases, it becomes more expensive.

Types of fiber optic cables

There are two basic types of fiber optic cable: multimode fiber and single-mode fiber. Single-mode fiber is used over long distances due to the small diameter of the glass fiber core, which reduces the chance for attenuation - reducing signal strength. The small opening separates the light into a single beam, which provides a more direct path and allows the signal to travel longer distances. Single-mode fiber has much more bandwidth than multimode fiber. The light source used for single-mode fiber is usually a laser. Single-mode fiber is usually expensive because precise calculations are required to produce laser light in a small opening.

Multimode fiber is used for short distances because the large core opening allows light signals to bounce and reflect further along the path. The large diameter allows multiple light pulses to be transmitted simultaneously through the cable, resulting in greater data transmission. This means that there is a greater chance of signal loss, reduction or interference. Multimode fiber optics typically use LEDs to create light pulses.

While copper wire cables are the traditional choice for telecommunications, networking and cable connections, fiber optics has become a common alternative. Most telephone company long-distance routes are now made with fiber optic cables. Optical fiber has more information than traditional copper wire due to its high bandwidth and fast speed. Because glass does not conduct electricity, fiber optics are not subject to electromagnetic interference and signal losses are minimized.