introduction to optical fiber communication (2)
DESCRIPTION
Introduction to Optical Fiber CommunicationTRANSCRIPT
![Page 1: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/1.jpg)
CETTM MTNL
1Introduction to Optical Fiber Comm.TOFCINT010
T818ITEC - SCAAP Training Programme
Mod Id :TOFCINT010
Introduction to Optical Fiber
Communications
![Page 2: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/2.jpg)
CETTM MTNL
2Introduction to Optical Fiber Comm.TOFCINT010
Historical Perspective
� One of the earliest known optical transmission
links :
� Was the use of a fire signal by the Greeks in the
eighth century B.C. for sending alarms, calls for
help or announcements of certain events.
� Most civilizations have used fire beacons, or
smoke signals to convey a single piece of
information.( victory in a war)
![Page 3: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/3.jpg)
CETTM MTNL
3Introduction to Optical Fiber Comm.TOFCINT010
INTRODUCTION
� In 1870, John Tyndall demonstrated the principle
of guiding light through internal reflections.
� In 1880, Alexander Graham Bell invented the
photo phone, which used unguided light to carry
speech.
� Major breakthrough was achieved with the
invention of laser in 1960.
![Page 4: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/4.jpg)
CETTM MTNL
4Introduction to Optical Fiber Comm.TOFCINT010
� In 1966, Charles K. Kao fabricated a low loss
glass fibre, giving a loss of 1000 dB/km.
� In 1970, Corning glass works, U.S.A. developed a
low loss fibre giving a loss of 20 dB/km.
� By 1972, losses were reduced to 4 dB/km.
� Today, the best fibres have a loss of < 0.2 dB/km.
Contd..
![Page 5: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/5.jpg)
CETTM MTNL
5Introduction to Optical Fiber Comm.TOFCINT010
TRANSMITTERINFORMATION
CHANNEL(MEDIUM)
RECEIVER
Basic Communication System
![Page 6: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/6.jpg)
CETTM MTNL
6Introduction to Optical Fiber Comm.TOFCINT010
Continued
� In optical communication transmission in an
optical format is carried out by varying the
intensity of the optical power.( intensity
modulation)
![Page 7: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/7.jpg)
CETTM MTNL
7Introduction to Optical Fiber Comm.TOFCINT010
Types of information channels
� Unguided channels
- Atmosphere is an unguided type of channel
over which waves can propagate.
� Guided channels
- Two wire lines, coaxial cable and waveguide
are the examples of guided information
channels
![Page 8: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/8.jpg)
CETTM MTNL
8Introduction to Optical Fiber Comm.TOFCINT010
�Privacy
�No weather dependence and
�The ability to convey messages within, under
and around physical structures.
Advantages of Guided channels
![Page 9: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/9.jpg)
CETTM MTNL
9Introduction to Optical Fiber Comm.TOFCINT010
Basic Fibre–Optic Link
![Page 10: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/10.jpg)
CETTM MTNL
10Introduction to Optical Fiber Comm.TOFCINT010
Fibre Optics
Optical fiber is a new medium, in which information
(voice, data or video) is transmitted through a
glass or plastic fiber, in the form of light.
![Page 11: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/11.jpg)
CETTM MTNL
11Introduction to Optical Fiber Comm.TOFCINT010
Basic elements of Transmitters
Transmitter convert electrical signal to optical
signals which is transmitted through fibre.
� Electronic interfaces.
� Electronic processing circuits.
� Drive circuitry.
� Light source – LED/Laser.
� Optical interface.
� Output sensing and stabilization.
� Temperature sensing and control
![Page 12: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/12.jpg)
CETTM MTNL
12Introduction to Optical Fiber Comm.TOFCINT010
Basic elements of an Optical Receiver
� Receiver- receives the optical signals from the
fibre and convert the same to its electrical
equivalent.
� Detector [PIN photodiode/APD (Avalanche
photodiode)]
� Detector used in fibre optical communications are
semiconductor photodiodes or photo-detectors
which converts the received optical signal into
electrical form.
� Amplifier
� Decision circuits.
![Page 13: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/13.jpg)
CETTM MTNL
13Introduction to Optical Fiber Comm.TOFCINT010
Information Transmission Sequence
![Page 14: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/14.jpg)
CETTM MTNL
14Introduction to Optical Fiber Comm.TOFCINT010
The transmission sequences are:
� Information is encoded into electrical signals.
� Electrical signals are converted into light
signals.
� Light travels down the fiber.
� A detector changes the light signals into
electrical signals.
� Electrical signals are decoded into information.
![Page 15: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/15.jpg)
CETTM MTNL
15Introduction to Optical Fiber Comm.TOFCINT010
Fiber Construction
� Consists of Core and Cladding
� Core and Cladding are made up of same material
� The material used is optically transparent
� Silica or borosilicate glass will be the usual
material
� The R.I of the core will be slightly higher than the
R.I of the cladding
![Page 16: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/16.jpg)
CETTM MTNL
16Introduction to Optical Fiber Comm.TOFCINT010
Contd…
� The core and cladding dia in mm
140100
12562.5
12550
1258
Cladding (µ m)Core (µ m)
![Page 17: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/17.jpg)
CETTM MTNL
17Introduction to Optical Fiber Comm.TOFCINT010
Material choice for low loss Optical Fiber
� Pure silica glass synthesized by fusing Sio2
molecules.
� R.I. Difference between core and cladding is
realized by the selective use of dopants during
fabrication processes.
![Page 18: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/18.jpg)
CETTM MTNL
18Introduction to Optical Fiber Comm.TOFCINT010
� Optical Fibres are non conductive (Dielectric)
– Grounding and surge suppression not
required.
- Cables can be all dielectric.
� Electromagnetic immunity
– Immune to electromagnetic interference
(EMI)
– No radiated energy.
– Unauthorized tapping difficult.
Advantages of Fiber Optics
![Page 19: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/19.jpg)
CETTM MTNL
19Introduction to Optical Fiber Comm.TOFCINT010
� Large Bandwidth (> 50 GHz for 1 km length)
– Future upgradability
– Maximum utilization of cable right of way.
– One time cable installation costs.
Continued
![Page 20: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/20.jpg)
CETTM MTNL
20Introduction to Optical Fiber Comm.TOFCINT010
� Low Loss (5 dB/km to < 0.25 dB/km typical)
– Loss is low and same at all operating
speeds within the fiber's specified ban
– Long, unrepeated links (> 70 km is
operation).
– Inexpensive light sources available.
– Repeater spacing increases along with
operating speeds because low loss fibers
are used at high data rates.
Continued
![Page 21: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/21.jpg)
CETTM MTNL
21Introduction to Optical Fiber Comm.TOFCINT010
� Small, light weight cables.
– Easy installation and handling.
– Efficient use of space.
� Available in Long lengths (> 12 kms)
- Less splice points
� Security
– Extremely difficult to tap a fiber as it does
not radiate energy that can be received by
a nearby antenna.
– Highly secure transmission medium.
Continued
![Page 22: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/22.jpg)
CETTM MTNL
22Introduction to Optical Fiber Comm.TOFCINT010
� Security – Being a dielectric
– It cannot cause fire.
– Does not attract lightning.
– It does not carry electricity.
– Can be run through hazardous areas
� Universal medium
– Serve all communication needs.
– Non–obsolescence.
Continued
![Page 23: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/23.jpg)
CETTM MTNL
23Introduction to Optical Fiber Comm.TOFCINT010
� Common carrier nationwide networks.
� Telephone inter–office trunk lines.
� Customer premise communication networks.
� Undersea cables.
� High EMI areas (Power lines, Rails, Roads).
� Factory communication/Automation.
� Control systems.
� Expensive environments.
� High lightning areas.
� Military applications.
� Classified (secure) communication
Applications of Fiber Optics in Comm.
![Page 24: Introduction to Optical Fiber Communication (2)](https://reader033.vdocuments.us/reader033/viewer/2022042616/563db972550346aa9a9d6ecb/html5/thumbnails/24.jpg)
CETTM MTNL
24Introduction to Optical Fiber Comm.TOFCINT010
Thank you