1. Understanding Fiber Optic Communications
Communications over hair-thin strands of glass
Presented by
This is a introduction to the technology of fiber optic communications, sending communications over hair thin strands of ultra-pure glass (and sometimes plastic).
This is aimed at students in secondary school or technical college science and vocational classes where fiber optics may be relevant. If optics, computers, television or telephones are covered in a science course, fiber optics is a relevant technology. Programs oriented toward certifications in electrical trades, electronics or computer technology are also appropriate venues for covering fiber optics.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

2. This presentation provided by The Fiber Optic Association, Inc.
The Professional Society Of Fiber Optics
The Fiber Optic Association is the professional society of fiber optics. It was founded in by a dozen fiber optic professionals who felt fiber optics needed an organization to promote a higher level of competence among fiber optic personnel through training and certification.
Today the FOA offers certification programs through about 100 schools worldwide and over 11,000 students have achieved FOA certification.
The FOA also participates in industry standards activities, educational programs (e.g. offering train-the-trainer programs) and participation in industry conferences.
The FOA is a non-profit educational organization supported primarily by certification fees from affiliated training schools.
Find out more about the FOA at
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

3. What Is Fiber Optics ?
Transmitting communications signals over hair thin strands of glass or plastic
Not a "new" technology
Concept a century old
Used commercially for last 25 years
The first commercial fiber optic installation was in for telephone signals in Chicago, installed in 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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

4. Fiber Has More Capacity
This single fiber can carry more communications than the giant copper cable!
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.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

5. Fiber Optic Communications
Applications include
Telephones
Internet
LANs - local area networks
CATV - for video, voice and Internet connections
Utilities - management of power grid
Security - closed-circuit TV and intrusion sensors
Military - everywhere!
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

6. Why Use Fiber Optics? Economics Speed Distance Weight/size
Freedom from interference
Electrical isolation
Security
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

7. Fiber Optic Applications
Fiber is already used in:
> 90% of all long distance telephony
> 50% of all local telephony
Most CATV networks
Most LAN (computer network) backbones
Many video surveillance links
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

8. 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
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

9. Fiber Optic Applications
Outside Plant vs Premises Installations
“Fiber optics” is not all the same. “Outside plant” refers to fiber optics as used outdoors in telephone networks or CATV. “Premises” fiber optics is used in buildings and on campuses.
Outside Plant: Telephone companies, CATV and the Internet all use lots of fiber optics, most of which is outside buildings. It hangs from poles, is buried underground, pulled through conduit or is even submerged underwater. Most of it goes relatively long distances, from a few thousand feet to hundreds of miles, over what we call “singlemode” fiber.
Premises Cabling: By contrast, premises cabling involves cables installed in buildings for LANs or security systems. It involves short lengths, rarely longer than a few hundred to two thousand feet, of mostly “multimode” fiber.
Both these applications are unique in the components they use, the installation methods and the testing procedures, but they share the basic principles we learn in this course.
FOTM, Chapter 2, DVVC, Chapter 10
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

10. Fiber Technology Presented By The Fiber Optic Association
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

11. Fiber Technology Presented By The Fiber Optic Association
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
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

12. Fiber Optic Data Links Presented By The Fiber Optic Association
Fiber optic transmission systems all consist of a transmitter which takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant.
The light is ultimately coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment.
Just as with copper wire or radio transmission, the performance of the fiber optic data link can be determined by how well the reconverted electrical signal out of the receiver matches the input to the transmitter.
FOTM, Chapter 2, DVVC, Chapter 11
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

13. Light Used In Fiber Optics
Fiber optic systems transmit using infrared light, invisible to the human eye, because it goes further in the optical fiber at those wavelengths.
The ultra-pure glass used in making optical fiber has less attenuation (signal loss) at wavelengths (colors) in the infrared, beyond the limits of the sensitivity of the human eye. The fiber is designed to have the highest performance at these wavelengths.
The particular wavelengths used, 850, 1300 and 1550 nm, correspond to wavelengths where optical light sources (lasers or LEDs) are easily manufactured.
Some advanced fiber optic systems transmit light at several wavelengths at once through a single optical fiber to increase data throughput. We call this method “wavelength division multiplexing.”
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

14. Wavelength-Division Multiplexing
How Does Wavelength-Division Multiplexing (WDM) Work?
It is easy to understand WDM. Consider the fact that you can see many different colors of light - red, green, yellow, blue, etc., all at once. The colors are transmitted through the air together and may mix, but they can be easily separated using a simple device like a prism, just like we separate the "white" light from the sun into a spectrum of colors with the prism.
The input end of a WDM system is really quite simple. It is a simple coupler that combines or multiplexes all the signal inputs into one output fiber. The demultiplexer separates the light at the end of the fiber. It shines the light on a grating (a mirror like device that works like a prism and looks similar to the data side of a CD) which separates the light into the different wavelengths by sending them off at different angles. Optics capture each wavelength and focuses it into another fiber, creating separate outputs for each wavelength of light.
Current systems offer from 4 to 32 channels of wavelengths. The higher numbers of wavelengths has lead to the name “Dense” Wavelength Division Multiplexing or DWDM.
FOTM, Chapter 3, DVVC, Chapter 10
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

15. Fiber Optic Cable Protects the fibers wherever they are installed
May have 1 to over fibers
Optical fibers are enclosed in cables for protection against the environment in which they are installed. Cables installed in trays in buildings require less protection than, for example, cables buried underground or placed under water.
Cables will include strength members, typically a strong synthetic fiber called aramid fiber or Kevlar for its duPont trade name, which takes the stress of pulling the cable. The thin yellow fibers in the photo are the strength members.
The outside of the cable is called the jacket. It is the final protection for the fibers and must withstand extremes of temperatures, moisture and the stress of installation. Some cables even have a layer of thin metal under the jacket to prevent rodents from chewing throught the cable.
The colors you see above are color-coding so you can identify individual fibers in the cable.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

16. Fiber Optic Connectors
Terminates the fibers
Connects to other fibers or transmission equipment
When a fiber needs to be connected to another, it can be spliced permanently by “welding” it at high temperatures or with adhesives, or it can be terminated with a connector that makes it possible to handle the individual fiber without damage.
Connectors align two fibers the size of a human hair such that little light is lost. Most connectors use ceramic cylinders about 2.5 mm in diameter with precisely aligned holes in the center that accept the fiber. Most connectors use adhesive to attach the fiber and the end is polished to a smooth finish.
Putting connectors on the end of fibers is a job that requires patience, skill and good training. Fiber optic technicians are expected to be able to install connectors properly.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

17. Jobs In Fiber Optics Designing components
Manufacturing fiber, lasers, etc.
Designing systems
Installing networks
Training and teaching
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.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

18. Fiber Optic Manufacturing
Facilities where fiber optic components (fiber, connectors, hardware) are manufactured need many highly educated and skilled workers. They operate machines costing as much as millions of dollars that make the precision components and test the quality of the products.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

19. Fiber Optic Installation - Outside Plant
Workers who install telephone and CATV fiber optic networks do much of their work outdoors, braving year-round weather. They operate big machines that dig trenches and lay and/or pull cables. Then they bring the ends of the cables into special trucks or trailers where lengths of cable are spliced together and tested.
Outside plant installations require more hardware (and more investment in the tools and test equipment.) Pullers, splicers, OTDRs and even splicing vans are the tools of the trade for OSP contractors.
FOTM, Chapter 9,12,13,15, DVVC, Chapter 11, 14
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

20. Fiber Optic Installation -Premises
Computer and security networks use lots of fiber which is installed inside buildings. Cables are pulled through conduits or laid in cable trays, then terminated in communications rooms. The installation on the left is in a crowded telecommunications closet of a bank while the right photo was taken in a computer room in the basement of a hundred year old college hall.
Premises installers need only a termination kit for attaching connectors and a simple test kit for their installations. Working in crowded telecom closets or communications rooms is the norm.
FOTM, Chapter 9,12,13,15, DVVC, Chapter 11, 14
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

21. Teaching Fiber Optics Presented By The Fiber Optic Association
Fiber optics, like any fast-growing technology, needs more trained workers. Some of those workers are trained in schools like yours, both in high schools and colleges, where general courses will prepare you for most any aspect of fiber optics. Some are trained by schools specializing in adult education, often aimed at specific applications, such as installing outside plant telecommunications cables underground, where instructors are usually experienced in the field themselves.
All these programs need qualified teachers.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

22. Learn More About Fiber Optics
The FOA Website,
Tech Topics
Links To Other Fiber Optic Websites
You can find more about fiber optics from the FOA website. The “Tech Topics” section includes many technical articles about fiber optics, and the “Links” page will lead you to more technical information and organizations.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

23. Two Good Textbooks Presented By The Fiber Optic Association
This presentation is based on 25 years of experience in the fiber optic business and much of the material is now in printed form in The Fiber Optic Technicians Manual and Data, Voice and Video Cabling, either or both of which may be used as a text for the course. References to the proper chapters are given in the notes. The notes give an overview of what the slide means and provide hints to explaining the meaning of the slide.
For the text references, FOTM means The Fiber Optic Technicians Manual and DVVC means Data, Voice and Video Cabling.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

24. For more information, also see Lennie Lightwave’s Guide To Fiber Optics www.LennieLightwave.com
Another good source of information is Lennie Lightwave’s Guide to Fiber Optics. You can see it on the web at and a printable version in PDF format is linked from the site.
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.

25. This presentation provided by The Fiber Optic Association, Inc.
The Professional Society Of Fiber Optics
Find out more about the FOA at
Presented By The Fiber Optic Association
©2004, The Fiber Optic Association, Inc.