The first commercial fiber optic installation was in for telephone signals in Chicago, installed in 1976. The first long distance networks were operational in the early 1980s. By 1985, most of todays basic technology was developed and being installed in the fiber optic networks that now handle virtually all long distance telecommunications. FOTM, Chapter 2, DVVC, Chapter 10
That tiny strand of optical fiber can carry more communications signals than the large copper cable in the background and over much longer distances. The copper cable has about 1000 pairs of conductors. Each pair can only carry about 24 telephone conversations a distance of less than 3 miles. The fiber cable carries more than 32,000 conversations hundreds or even thousands of miles before it needs regeneration. Then each fiber can simultaneously carry over 150 times more by transmitting at different colors (called wavelengths) of light. The cost of transmitting a single phone conversation over fiber optics is only about 1% the cost of transmitting it over copper wire! That’s why fiber is the exclusive medium for long distance communications.
These are but a few of the applications of fiber optics, as we concentrate on communications. Fiber optics are also used for lighting, signs, sensors and visual inspection (medicine and non-destructive testing). FOTM, Chapter 2, DVVC, Chapter 10
The biggest advantage of optical fiber is the fact it can transport more information longer distances in less time than any other communications medium. In addition, it is unaffected by the interference of electromagnetic radiation which makes it possible to transmit information and data with less noise and less error. Fiber is lighter than copper wires which makes it popular for aircraft and automotive applications. These advantages open up the doors for many other advantages that make the use of optical fiber the most logical choice in data transmission. FOTM, Chapter 2, DVVC, Chapter 10
About the only place fiber has not become the dominant cable is desktop connections for LANs. Priced to just replace copper, it is more expensive, but using a centralized fiber architecture, fiber allows the removal of electronics from the telecom room and ends up being less expensive! FOTM, Chapter 2, DVVC, Chapter 10
Singlemode fiber used in telecommunications and CATV has a bandwidth of greater than a terahertz. Standard systems today carry up to 64 channels of 10 gigabit signals - each at a unique wavelength. FOTM, Chapter 2, DVVC, Chapter 10
where ∇ 2 is the Laplacian , k is the wavenumber , and A is the amplitude .
Optical fiber is comprised of a light carrying core surrounded by a cladding which traps the light in the core by the principle of total internal reflection. Most optical fibers are made of glass, although some are made of plastic. The core and cladding are usually fused silica glass which is covered by a plastic coating called the buffer or primary buffer coating which protects the glass fiber from physical damage and moisture. There are some all plastic fibers used for specific applications. Glass optical fibers are the most common type used in communication applications. FOTM, Chapter 2, DVVC, Chapter 11
By making the core of the fiber of a material with a higher refractive index, we can cause the light in the core to be totally reflected at the boundary of the cladding for all light that strikes at greater than a critical angle determined by the difference in the composition of the materials used in the core and cladding. Many students are curious how fiber is made. Good explanations are available in the FOTM, on the Fiber Optic Association website under “Tech Topics” and from most fiber manufacturers. FOTM, Chapter 2, DVVC, Chapter 11
There are lots of jobs available in fiber optics. Each has unique requirements and requires different educational backgrounds. Designers: Most of those who design components have at least a undergraduate degree. For components like connectors, it would be in mechanical engineering. Optical components like fibers require knowledge of both optics and materials, so many designers will have degrees in physics, chemistry or materials.If you want to develop lasers or photodetectors, you should have a background in solid-state physics. Manufacturing jobs will have differing requirements depending on the technical nature of the job. Some require manual skills while others may require advanced technical education to understand the complicated manufacturing processes. Designers of fiber optic systems are usually electronic engineers. Fiber optic components are used like integrated circuits to develop communications systems. Installers must be skilled in the process of pulling cables, then splicing and terminating them. It requires more manual dexterity than the other jobs, plus a basic understanding of how the systems work.
What Is Fiber Optics ?• Not a "new" technology• Concept a century old• Used commercially for last 36 years
Fiber Has More CapacityThis single fibercan carry morecommunicationsthan the giantcopper cable!
Fiber Optic Communications• Applications include – Telephones – Internet – LANs - local area networks – CATV - for video, voice and Internet connections
Why Use Fiber Optics?• Economics• Speed• Distance• Weight/size• Freedom from interference• Security
Fiber Optic Applications• Fiber is already used in: – > 90% of all long distance telephony – > 50% of all local telephony – Most LAN (computer network) backbones – Many video surveillance links
Fiber Optic Applications• Fiber is the least expensive, most reliable method for high speed and/or long distance communications• While we already transmit signals at Gigabits per second speeds, we have only started to utilize the potential bandwidth of fiber
SINGLE MODE FIBER OPTICSIn fiber-optic communication, a single-mode optical fiber (SMF)(monomode optical fiber, single-mode optical waveguide, orunimode fiber) is an optical fiber designed to carry only a singleray of light (mode). Modes are the possible solutions of theHelmholtz equationfor waves, which is obtained by combining Maxwells equations and theboundary conditions. These modes define the way the wave travelsthrough space, i.e. how the wave is distributed in space. Waves canhave the same mode but have different frequencies. This is the case insingle-mode fibers, where we can have waves with different frequencies,but of the same mode, which means that they are distributed in space inthe same way, and that gives us a single ray of light. Although the raytravels parallel to the length of the fiber, it is often calledtransverse mode since its electromagnetic vibrations occurperpendicular (transverse) to the length of the fiber(where ∇2 is the Laplacian, k is the wave number, and A is the amplitude.)
Multimode Fiber (Multi Mode Fiber) Fibers that carry more than one mode are called multimode fibers. There are two types of multimode fibers. One type is step- index multimode fiber and the other type is graded-index multimode fiber.
step-index multimode fiberStep index Multimode fibers for laser power medicine andindustry applicationsStep index Multimode fiber with ultra-high stability,reliability and long fiber life time for high power lasertransmission
Graded-index multimode fiber (GRIN)is a compromise between single-mode fibers andmultimode fibers. It offers bandwidth potential higher than MMF,but lower than SMF, yet it has the light-gathering capability ofMMF.
2. Bandwidths of up to 10Gbps4. Streaming Whole Movies in HD6. Effortless video conferencing with no lagging8. Gaming in HD quality that never lags
ADVANTAGES OF OPTICAL FIBERS1.VERY HIGH INFORMATION CARRING CAPACITY.2.LESS ATTENUATION (order of 0.2 db/km)3.SMALL IN DIAMETER AND SIZE & LIGHT WEIGHT4.LOW COST AS COMPARED TO COPPER5.FLEXIBLE AND EASY TO INSTALL IN TIGHT CONDUICTS6.ZERO RESALE VALUE7.DIFFICULT TO TAP FIBERS, SO SECURE8.NO CROSS TALK AND DISTURBANCES
Jobs In Fiber Optics• Designing components• Manufacturing fiber, lasers, etc.• Designing systems• Installing networks• Training and teaching