Introduction Optical Fiber Communication.pptx

Mumbai University
Optical Communication & Networks Sem VIII

1. OPTICAL COMMUNICATION Presented By: Prof. Shailaja Udtewar Department of EXTC Xavier Institute of Engineering, Mumbai

2. Topics Transmission Media Types of Transmission Media

3. Transmission Media

4. Transmission Media For any networking to be effective, raw stream of data is to be transported from one device to other over some medium. Various transmission media can be used for transfer of data.

5. Types of Transmission Media

6. Types of Transmission Media These transmission media may be of two types − Guided − In guided media, transmitted data travels through cabling system that has a fixed path. For example, copper wires, fibre optic wires, etc. Unguided − In unguided media, transmitted data travels through free space in form of electromagnetic signal. For example, radio waves, lasers, etc. Each transmission media has its own advantages and disadvantages in terms of bandwidth, speed, delay, cost per bit, ease of installation and maintenance, etc.

7. Types of Transmission Media

8. Twisted Pair Cable

9. Twisted Pair Cable Copper wires are the most common wires used for transmitting signals because of good performance at low costs. If two or more wires are lying together, they can interfere with each other’s signals. To reduce this electromagnetic interference, pair of copper wires are twisted together in helical shape like a DNA molecule called twisted pair . To reduce interference between nearby twisted pairs, the twist rates are different for each pair. Up to 25 twisted pair are put together in a protective covering to form twisted pair cables that are the backbone of telephone systems and Ethernet networks

10. Advantages of twisted pair cable Twisted pair cable are the oldest and most popular cables all over the world. This is due to the many advantages that they offer Trained personnel easily available due to shallow learning curve Can be used for both analog and digital transmissions Least expensive for short distances Entire network does not go down if a part of network is damaged

11. Disdvantages of twisted pair cable Twisted pair cables offer some disadvantages too Signal cannot travel long distances without repeaters High error rate for distances greater than 100m Very thin and hence breaks easily Not suitable for broadband connections

12. Twisted Pair Cables Twisted Pair cables Unshielded Twisted Pair Shielded Twisted pair

13. Twisted Pair Cables

14. Unshielded Twisted Pair Cable The wires that are not shielded but simply bundled together in a protective sheath are called unshielded twisted pair (UTP) cables . These cables can have maximum length of 100 metres . UTP are more popular than STP (Shielding makes cable bulky) UTP cables used as last mile network connection in homes and offices.

15. UTP Cable

16. Unshielded Twisted Pair (UTP) cable  is most certainly by far the most popular cable around the world. UTP cable is used not only for networking but also for the  traditional telephone  ( UTP-Cat 1 ). There are  7 different types of UTP categories  and, depending on what you want to achieve, you would need the appropriate type of cable.  UTP Cable

17. UTP Cable Types Cat 7 Cat 6 Cat 5e Cat 5 Cat 4 Cat 3 Cat 2 Cat 1 U T P

18. Category Description CAT1 Used for voice only, not data CAT2 4 Mbps; token ring networks CAT3 10 Mbps; standard Ethernet CAT4 16 Mbps; token ring networks CAT5 100 Mbps; Ethernet and Fast Ethernet CAT5e 155 Mbps; Fast Ethernet and Gigabit Ethernet; largely replaces Cat 5 CAT6 600 Mbps; more fragile than Cat 5 or 5e CAT7 Theoretical; up to 1 Gbps UTP Cable Types UTP-CAT5e  is the most popular UTP cable which came to replace the old coaxial cable that was not able to keep up with the constant growing need for faster and more reliable networks.

19. UTP Cable Types "A   token ring network  is a local area  network  (LAN) in which all computers are connected in a  ring  or star topology and a bit- or  token -passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time.

20. UTP PROS : Most flexible cheapest cable (but requires expensive support components) easy to install easy to add users CONS : Shortest usable cable length susceptible to electrical interference unsecure generally not good for use between buildings

21. Shielded Twisted Pair Cable To counter the tendency of twisted pair cables to pick up noise signals, wires are shielded in the following three ways − Each twisted pair is shielded. Set of multiple twisted pairs in the cable is shielded. Each twisted pair and then all the pairs are shielded. Such twisted pairs are called shielded twisted pair (STP) cables .

22. STP Shielded twisted pair (STP) is similar to UTP except it contains a copper braid jacket to ‘shield’ the wires from electrical interference . It can support transmissions over greater distances than UTP.

23. Coaxial Cable

24. Coaxial cable Coaxial cables are copper cables with better shielding than twisted pair cables, so that transmitted signals may travel longer distances at higher speeds. A coaxial cable consists of these layers, starting from the innermost − Stiff copper wire as core Insulating material surrounding the core Closely woven braided mesh of conducting material surrounding the insulator Protective plastic sheath encasing the wire Coaxial cables are widely used for cable TV connections and LANs .

25. Coaxial cable

26. Advantages of Coaxial cable Inexpensive Easy to wire and install Easy to expand Good resistance to EMI Up to 10Mbps capacity Durable Another benefit of coaxial cable is the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This means coaxial cable can be installed next to metal objects without losing power, unlike other types of transmission lines.

27. Disadvantages of Coaxial cable The main disadvantage of using coaxial cable is that single cable failure can take down an entire network.

28. Coaxial cable The transmission speed of coaxial cable is 10Mbps (megabits per second), and they offer 80 times more transmission capacity than twisted pair cables. Supports data transfer rates from 1 Mbps to 100 Mbps Transfer rate of 10 Mbps common for LAN Types: RG-6, RG-8, RG-11, RG-58, RG-59

29. First, What is RG? Type Segment Length Use RG-6 N/A TV and video; similar to RG-59 but for longer distances RG-8 500 m Thick Ethernet (10 Base 5) RG-11 500 m Broadband LAN connections RG-58 185 m Thin Ethernet (10 Base 2) RG-59 305 m Cable TV, video; often for short distances (6 feet)

30. The IEEE shorthand identifiers, such as  10Base5, 10Base2, 10BaseT, and 10BaseF  include three pieces of information: The number 10:  At the front of each identifier, 10 denotes the standard data transfer speed over these media - ten megabits per second (10Mbps). The word Base:  Short for Baseband, this part of the identifier signifies a type of network that uses only one carrier frequency for signaling and requires all network stations to share its use. The segment type or segment length:  This part of the identifier can be a digit or a letter: Digit -  shorthand for how long (in meters) a cable segment may be before attenuation sets in. For example, a 10Base5 segment can be no more than 500 meters long   Letter -  identifies a specific physical type of cable. For example, the T  at the end of 10BaseT stands for twisted-pair.

31. 10Base2— An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments i . e Max length=200m 10Base5— An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with 5 continuous segments not exceeding 100 meters per segment. i . e Max length=500m 10BaseT— An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling and twisted pair cabling.

32. Each transmission media has its own advantages and disadvantages in terms of bandwidth, speed, delay, cost per bit, ease of installation and maintenance, etc.

33. Twisted pair, Coaxial & Optical Fiber

34. Optical Fiber

35. Capacity ! Capacity ! and More Capacity ! During past three decades, remarkable and dramatic changes took place in the electronic communication industry. A phenomenal increase in voice , data and video communication - demands for larger capacity and more economical communication systems. Radio-waves, Terrestrial and Microwave systems have long since reached their capacity. Why Fiber Optic Technology?

36. An optical fiber is a cylindrical wave guide made of transparent dielectric, (glass or clear plastic), which guides light waves along its length by total internal reflection. It is very thin like human hair, approximately 70µm or 0.003 inch diameter. The thin strand of a metal is called a wire and a thin strand of dielectric materials is called a Fiber. What is Optical Fiber ?

37. Optical Fiber Structure

38. Optical Fiber Structure

39. Optical Fiber Structure The general structure of optical fibers includes the following three parts. Core Cladding Jacket

40. Core The core is the innermost part that is made out of glass or transparent plastic. It is extremely thin, flexible, and has a cylindrical shape. Its sole purpose is to keep all the light within itself and also to guide the light in a direction parallel to its axis. Since it is the primary carrier and guide of the light waves, it can be called an optical waveguide.

41. Cladding The cladding is the second layer on top of the core. It is also  made of glass or transparent plastic. Refractive index of the cladding is lower than that of the core.

42. Jacket The jacket exists purely for protecting the core and the cladding. It is made up of flexible and abrasion-resistant varieties of plastic. Usually, the jacket has another layer beneath it called a buffer. The buffer and the jacket together protect the optical fiber from environmental and physical damage.

43. Fiber Optic Communication It is the method of communication in which signal is transmitted in the form of light and optical fiber is used as a medium of transmitting those light signal from one place to another. The signal transmitted in optical fiber is converted from the electrical signal into light and at the receiving end, it is converted back into the electrical signal from the light.

44. Fiber Optic Communication The data sent can be in the form of audio, video or telemetry data that is to be sent over long distances or over Local Area Networks. Optical fiber communication having good results in long-distance data transfer at high speed, it has been used as an application for various communication purposes.

45. Fiber Optic Communication Works? The Optical fiber communication process transmits a signal in the form of light which is first converted into the light from electrical signals and transmitted, and then vice versa happens on the receiving side. This process can be explained using a diagram as shown below:

46. Fiber Optic Communication Works?

47. Fiber Optic Communication Works? Transmitter side: On the transmitter side, if the data is analog, it is sent to a coder or converter circuit which converts the analog signal into digital pulses of 0,1,0,1…(depending on how the data is) and passed through a light source transmitter circuit . If the input is digital then it is directly sent through the light source transmitter circuit which converts the signal in the form of light waves.

48. Fiber Optic Communication Works? Optical Fiber Cable: The light waves received from the transmitter circuit to the fiber optic cable is now transmitted from the source location to the destination and received at the receiver block.

49. Fiber Optic Communication Works? Receiver Side: On the receiver side photocell (light detector), receives light waves from optical fiber cable, amplifies it using amplifier and converts it into proper digital signal. If the output source is digital then signal is not changed further and if output source needs analog signal then the digital pulses are then converted back to an analog signal using the decoder circuit. The whole process of transmitting an electrical signal from one point to the other by converting it into the light and using Fiber optic cable as transmission source is known as Optical Fiber Communication .

50. It permits transmission over longer distances and at higher bandwidths than other forms of communication Its working is based on principle of Total Internal Reflection. Its function is to guide visible and infrared light over long distance. T otal Internal Reflection (TIR)

51. T otal Internal Reflection (TIR)

52. T otal Internal Reflection (TIR) ..\OC Videos 2020-21\TIR TYNDALL EFFECT(360p).mp4

53. Optical Region

54. Wider bandwidth Abundant raw material Low loss Compact and light weight Higher Security Immunity to RFI Immunity to EMI No cross-talk Less Corrosion Less temperature sensitive Advantages

55. Advantages of Optical Fiber Wide r Bandwidth: Optical carrier frequency is in range of 10 13 to 10 16 HZ. The information carrying capacity C of a system is directly proportional to its BW. Wider the BW, greater the information carrying capacity. C = BW×log 2 (1+SNR)

56. Abundant Raw Material : Optical fibers made from Silica ( Sand). Not a scarce resource in comparison to copper. Low loss : Information can be sent over a large distance . Losses ~ 0.2 dB/km. Repeater spacing >100 km with bit rates in Gbps . Advantages of Optical Fiber

57. Compact & light weight: Smaller size : Fiber thinner than human hair Typical optical cable fiber dia 125 µm, cable dia 2.5 mm and weight 6 kg/km. A coaxial cable (RG-19/U), outer dia 28.4 mm, and weight 1110 kg/km. Higher Security: No radiations Difficult to tap. Attractive for Defense, Intelligence and Banks Networks. Advantages of Optical Fiber

58. Advantages Immunity to RFI Fibers have excellent rejection of radio-frequency interference (RFI) caused by radio and television stations, radar, and other electronics equipment. Immunity to EMI: Fibers have excellent rejection of electromagnetic interference (EMI caused by natural phenomena such as lightning, sparking, etc). No cross-talk The optic wave within the fiber is trapped; none leaks out during transmission to interfere with signals in other fibers.

59. Less Corrosion: Corrosion caused by water/chemicals is less severe for glass than for copper. Less temperature sensitive: Glass fibers can withstand extreme temperatures . G lass fiber unaffected. Advantages

60. Practical Disadvantages Optical fibers are relatively expensive. Optical fibers are more fragile than electrical wires. Glass can be affected by hydrogen gas (underwater cables). Most fibers become opaque when exposed to radiation. Connector installation is time consuming and highly skilled operation . Splicing of fibers is expensive equipment & skilled operators . Difficult to tap in and out need expensive couplers .

61. Applications Telecommunications Long-Distance Transmission Inter-exchange junction Fiber in the loop ( FITL) -- FTTC , FTTB , FTTH Video Transmission Television broadcast, cable television (CATV), remote monitoring, etc. Broadband Services P rovisioning of broadband services, such as video request service , home study courses, medical facilities, etc. High EMI areas Along railway track, through power substations can be suspended directly from power line towers, or poles. Military applications Non-communication fiber optics: e.g. fiber sensors.

62. Optical Fiber Impact on IoT Fast Transmission Media - The future will be IOT and all of our devices and things will be connected to the internet, which needs good communication and high speed. The only transmission media that supports such a requirement is Optical Fiber. The future needs IOT and IOT need Optical fiber for best communication that could help reach Wireless data speed up to 100 Gbps speed, making communications and large size data transfer in seconds.

63. Optical Fiber Impact on IoT (Internet of Things) Data Security – Security in IoT is the main concern when we think of large amount of data to be transferred between billions of devices connected together. Hacking of data from communication media is possible unless it is Optical fiber. The optical fibers are very difficult to hack and hacking them without being detected is like next to impossible. So again, an optical fiber can help secure the data and transfer it at very high speed. No data loss due to interference - The optical fiber cables can be installed anywhere (even underwater or at high-temperature areas) and don’t have any electromagnetic interference resulting in no data loss due to interference.

64. Fiber Optics Timeline 1957 : First fiber-optic endoscope tested on a patient. 1960 : Invention of Laser (development, T Maiman ) 1962: semiconductor laser introduced - most popular type of laser in fiber optics 1966 : Kao and Hockham were first to reduce attenuation in optical fibers below 20 (dB/km) making it a practical communication medium (Nobel Prize 2009) 1970 : Researchers at Corning developed a glass fiber with less than a 20dB/km loss 1972 : First Semiconductor diode laser was developed 1977 : GT&E in Los Angeles and AT&T in Chicago send live telephone signals through fiber optics (850nm, MMF, 6 Mbps, 9km ) - World’s first FO link

65. Fiber Optics Timeline John Tyndall

66. John Tyndall (1870) John Tyndall, using a jet of water that flowed from one container to another and a beam of light, demonstrated that light used internal reflection to follow a specific path. As water poured out through the spout of the first container, Tyndall directed a beam of sunlight at the path of the water. The light, as seen by the audience, followed a zigzag path inside the curved path of the water.

67. Developed an optical voice transmission system called photophone . The photophone used free-space light to carry the human voice 200m Specially placed mirrors reflected sunlight onto a diaphragm attached within the mouthpiece of the photophone . At the other end, mounted within a parabolic reflector, was a light-sensitive selenium resistor. Alexander Graham Bell (1880)

68. This resistor was connected to a battery that was, in turn, wired to a telephone receiver. As one spoke into the photophone , the illuminated diaphragm vibrated, casting various intensities of light onto the selenium resistor. The changing intensity of light altered the current that passed through the telephone receiver which then converted the light back into speech. Bell believed this invention was superior to the telephone because it did not need wires to connect the transmitter and receiver. Fiber Optics Timeline

69. The Light Dependent Resistor Cell

70. The Nobel Prize in Physics 2009 Charles K. Kao (b. 1933 Shanghai, China) Standard Telecommunication Laboratories, Harlow, UK; Chinese University of Hong Kong, Hong Kong, China "For ground breaking achievements concerning the transmission of light in fibers for optical communication " "For the invention of an imaging semiconductor circuit – the CCD sensor" Willard S. Boyle b. 1924 George E. Smith b. 1930 Bell Laboratories, Murray Hill, NJ, USA

71. History of Optical Communication Optical communication systems date back to the 1790s, to the optical semaphore telegraph invented by French inventor Claude Chappe. In 1880 , Alexander Graham Bell patented an optical telephone system, which he called the Photophone. However, his earlier invention, the telephone, was more practical and took tangible shape. The Photophone remained an experimental invention and never materialized. During the 1920s , John Logie Baird in England and Clarence W. Hansell in the United States patented the idea of using arrays of hollow pipes or transparent rods to transmit images for television or facsimile systems.

72. History of Optical Communication In 1954 , Dutch scientist Abraham Van Heel and British scientist Harold H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers, whereas Van Heel reported on simple bundles of clad fibers. Van Heel covered a bare fiber with a transparent cladding of a lower refractive index. This protected the fiber reflection surface from outside distortion and greatly reduced interference between fibers.

73. History of Optical Communication Abraham Van Heel is also notable for another contribution. Stimulated by a conversation with the American optical physicist Brian O'Brien, Van Heel made the crucial innovation of cladding fiber-optic cables. All earlier fibers developed were bare and lacked any form of cladding, with total internal reflection occurring at a glass-air interface. Abraham Van Heel covered a bare fiber or glass or plastic with a transparent cladding of lower refractive index. This protected the total reflection surface from contamination and greatly reduced cross talk between fibers.

74. History of Optical Communication By 1960 , glass-clad fibers had attenuation of about 1 decibel (dB) per meter, fine for medical imaging, but much too high for communications. In 1961 , Elias Snitzer of American Optical published a theoretical description of a fiber with a core so small it could carry light with only one waveguide mode. Snitzer's proposal was acceptable for a medical instrument looking inside the human, but the fiber had a light loss of 1 dB per meter. Communication devices needed to operate over much longer distances and required a light loss of no more than 10 or 20 dB per kilometer.

75. History of Optical Communication By 1964 , a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices, the 10 or 20 dB of light loss per kilometer standard. Dr. Kao also illustrated the need for a purer form of glass to help reduce light loss. In the summer of 1970 , one team of researchers began experimenting with fused silica, a material capable of extreme purity with a high melting point and a low refractive index.  Corning Glass researchers Robert Maurer, Donald Keck, and Peter Schultz invented fiber-optic wire or "optical waveguide fibers" (patent no. 3,711,262), which was capable of carrying 65,000 times more information than copper wire , through which information carried by a pattern of light waves could be decoded at a destination even a thousand miles away.

76. History of Optical Communication The team had solved the decibel-loss problem presented by Dr. Kao. The team had developed an SMF with loss of 17 dB/km at 633 nm by doping titanium into the fiber core. By June of 1972 , Robert Maurer, Donald Keck, and Peter Schultz invented multimode germanium-doped fiber with a loss of 4 dB per kilometer and much greater strength than titanium-doped fiber. By 1973 , John MacChesney developed a modified chemical vapor-deposition process for fiber manufacture at Bell Labs. This process spearheaded the commercial manufacture of fiber-optic cable.

77. History of Optical Communication In April 1977 , General Telephone and Electronics tested and deployed the world's first live telephone traffic through a fiber-optic system running at 6 Mbps , in Long Beach, California. They were soon followed by Bell in May 1977 , with an optical telephone communication system installed in the downtown Chicago area, covering a distance of 1.5 miles (2.4 kilometers). Each optical-fiber pair carried the equivalent of 672 voice channels and was equivalent to a DS3 circuit. Today more than 80 percent of the world's long-distance voice and data traffic is carried over optical-fiber cables.

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