SHREEJEE INSTITUTE OF TECHNOLOGY AND MANAGEMENT

Optical Fiber

• Guided by:- Mr. Prakash Singh Chouhan

• By:- Shubham Yadav• EC BRANCH 1ST YEAR

What is Optical Fiber?• An Optical fiber is a flexible, transparent fiber made of high quality

glass (silica) or plastic, slightly thicker than a human hair.• It either functions as a waveguide or light pipe that transmits light

between two ends of the fiber or fiber cable.• Optical fibers are widely used in fiber-optic communications, which

permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication

• Fibers are used instead of metal wires because signals travel along them with less loss and are also safe to electromagnetic interference.

• The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics.

History of Fiber Optics

• Fiber optics is not really a new technology, its fairly old.

• Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon and Jacques Babinet in Paris in the early 1840s

What is it made of?

• Silica• Plastic• Fluoride• Phosphates

Uses of Optical Fiber

• Fiber optic can accommodate variety of needs.• It can be used in Communication, fiber optic sensors,

illumination, medical.• And also in other places where bright light needs to

be shone on a target without a clear line-of-sight path.• Used in building to route sunlight from the roof to

other parts of the building.• And many more usages but we will only discuss use of

optical fiber in communication here.

In Communication• Optical fiber can be used as a medium for

telecommunication and computer networking because it is flexible and can be bundled as cables.

• It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables.

• The per-channel light signals propagating in the fiber have been modulated at rates as high as 111 gigabits per second (Gbit/s) by NTT, although 10 or 40 Gbit/s is typical.

• In June 2013, researchers demonstrated transmission of 400 Gbit/s over a single channel.

Continued…

• Each fiber can carry many independent channels, each using a different wavelength of light.

• As of 2011 the record for bandwidth on a single core was 101 Tbit/sec (370 channels at 273 Gbit/sec each).

• The record for a multi-core fibre as of January 2013 was 1.05 petabits per second

Details of Fiber Optics

• If you look closely at a single optical fiber, you will see that it has the following parts:

– Core - Thin glass center of the fiber where the light travels

– Cladding - Outer optical material surrounding the core that reflects the light back into the core

– Buffer coating - Plastic coating that protects the fiber from damage and moisture

Total Internal ReflectionRefraction is the changing direction of light when it

goes into a material of different density.

The critical angle is the angle of incidence that will

produce a 900 angle of refraction.

Material 1 is more dense than material 2, so n1 is greater than n2.

Continued…

How Fibber Optics transmit data

• a

Shaper Decoder

Photocell or light

detector

Amplifier

Original voice or video

Coder and Converter

Light Source Transmitter

Pulses

Information Input (Voice

or video)

Types of FiOs

–Single Mode Fiber.– It uses a laser-diode arrangement to transmit the

light signal.– It uses a single ray of light in the transmission

process.– It can be used for longer fiber runs (it can

traverse up to 40 km without a repeater).

Continued…–Multi Mode Fiber.– It uses an infrared LED system to transmit the

light signal.– It uses multiple rays of light (more signals down

the path).– It is used for shorter fiber runs (under 2 km).– It is less expensive to implement than SMF.– The most common application in networking

utilizes MMF 62.5/125µm cables, with a maximum distance of 275 m.

Areas of Application

* Telecommunications* Local Area Networks* Cable TV* CCTV* Optical Fiber Sensors

FiOs Advantages• a

Bandwidth · High bandwidth and capacity· Lower signal attenuation (loss)

Immunity to Electrical Noise, Electromagnetic Immunity

· Immune to noise (electromagnetic interference [EMI] · No crosstalk· Lower bit error rates

Signal Security · Difficult to tap· Nonconductive (does not radiate signals)

Size and Weight · Reduced size and weight cables

Overall System Economy · Low overall system cost· Lower installation cost

Reliability · Less restrictive in harsh environments

FiOs Disadvantages• a

Interfacing Costs•High planning, installation, and maintenance cost

Strength •lower tensile strength than coaxial cable

Remote Powering of Devices

•necessary to provide electrical powerto a remote device.• Cannot be achievedthrough the fiber, metallic conductors are often included in the cable assembly.

Inability to interconnect •incompatibility with the electronic hardware systems that make up today's world.

Loss in Optical Fiber• Losses vary greatly depending upon the type of fiber– Plastic fiber may have losses of several hundred dB per

kilometer– Graded-index multimode glass fiber has a loss of about 2–

4 dB per kilometer

– Single-mode fiber has a loss of 0.4 dB/km or less