OPTICAL FIBER COMMUNICATION

Prepared by : -Bhavishya GargMohit sutharBharat parmarPrashant sharma

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53 Engineers , 53 Vehicles , 53 drivers , 104 labor, 107 patrollers ………

OFC Network

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…along with the SME , Fiber Lead and round the clock OMCR…. Are engaged in maintaining the 13,01,5 kilometer fiber network .

OFC Network

Our patrollers travel approx twelve thousand kilometers on daily basis

HOW FIBRE WORKSThe operation of an Optical Fibre is based on the principle of Total Internal Reflection (TIR).

Light reflects or refracts (bends) depending on the angle at which it strikes a surface. This occurs because different interfaces between materials refract light in different ways.

81 8181 81

n1

n2

n3n=1.49

n=1.48

n=1.8

MULTI MODE:Multi mode fiber was the first type of commercial fiber, which has larger core diameter (50 or 62.5nm) allowing multiple modes of light to propagate through the fiber simultaneously.

It is used primarily for short distances (<2KM) such as LAN communication, due to more loss and less bandwidth capacity.

SINGLE MODE:Single Mode fiber has a much smaller core (8-10nm) that allows only one mode of light at a time to propagate through the core.

This is widely used for all voice/data transmission applications over long distances and high capacities.

125micrometre

8-10 micrometre

125 micrometre

50 - 62.5 micrometre

Single Mode Multi Mode

TYPES OF FIBER USED IN CUMMUNICATION

DEFINITIONmechanical device for joining two pieces of paper or film or magnetic tape or fibers

process of the permanent connection of two pieces of optical fibers is called Splicing

mechanical splicing fusion splicing

Splicing

TYPES OF SPLICING

MECHANICAL SPLICING bonding two fibers

together in an alignment structure

Transparent adhesive - e.g. epoxy resin Commonly used

groove - V-groove

TYPES OF SPLICING

FUSION SPLICING Fusing the two fibers

Flame heating sources - micro-plasma burners, oxy-

hydric micro-burners, electric arc..

Advantage - consistent and easily controlled

heat with adaptability

Possible drawback - weakening of fiber in the vicinity

of splice

TYPES OF SPLICING

COMPARISON

Mechanical splicing Fusion splicing

Reflection losses(-45 db to -55 db)

No reflection losses

Insertion loss(0.2 db)

Very low insertion loss(0.1 db to .15 db)

cost – high Comparatively less

HOW TO IDENTIFY THE FACTORS WHICH GIVES HIGH LOSS ???

1. Clean the fiber and the V-Grooves well to ensure that the external parametersare not affecting the splice loss.

2. View the splice parameters while splicing so that the cleave angle, view angle and geometry of the fiber can be verified.

3. Check whether the machine is okay.

FUSION SPLICER

FSM-16S

manufacturer : Fujikura

manufacturer : Ericsson

SPLICER CLOSER

TEST INSTRUMENTS

OTDR : Optical Time Domain Reflectometer -To detect faults/breaks in the FO links.

Optical Power Meter : To measure the optical power at the end of Fibre.

Optical Source : To send light source in to the Fibre for testing- Laser/LED.

• Single-ended measurement tool• Provides a detailed picture of section-by-section loss• Operates by sending a high-power pulse of light down the fiber and

measuring the light reflected back• Uses the time it takes for individual reflections to return to determine

the distance of each event• Measures/characterizes:

Fiber attenuationAttenuation example (new G.652.C fibers)

0.33 dB/km at 1310 nm (0.35 dB/km for worst case)0.21 dB/km at 1490 nm (0.27 dB/km for worst case)0.19 dB/km at 1550 nm (0.25 dB/km for worst case)

What is an optical time-domain reflectometer (OTDR)?

OTDR BASIC PRINCIPLES

OTDR Basic Principles An OTDR sends short pulses of light into a fiber. Light scattering occurs in the fiber due to discontinuities such as connectors, splices, bends, and faults. An OTDR then detects and analyzes the backscattered signals. The signal strength is measured for specific intervals of time and is used to characterize events.

The OTDR to calculate distances as follows:

Distance = c/n * t/2

c = speed of light in a vacuum (2.998 x 108 m/s)

t = time delay from the launch of the pulse to the reception of the pulse

n = index of refraction of the fiber under test (as specified by the manufacturer)

REFLECTOMETRY THEORY

• The OTDR launches short light pulses (from 5 ns to 20 µs)

• Measuring the difference between the launching time and the time of arrival of the returned signal, it determines the distance between the launching point and the event.

GIS :GEOGRAPHIC INFORMATION SYSTEM

WHAT IS GIS :

Geographic information system (GIS): a computer-based information system that enables capture, modeling, storage, retrieval, sharing, manipulation, and presentation of geographically referenced data