Optical Fiber AUTO Optics and Spectroscopy Spring 2012 Miguel Angel Chourio Masters degree in Telecommunication Engineering University of Vaasa, Finland

What is a Optical Fiber Single Mode Optical Fiber Multimode Optical Fiber Single mode Vs. Multimode Fiber Snews Law - Total Internal Reflection How is glass optical Fiber made Applications Conclusions References INDEX

Optical Fiber Optical Fiber uses glass to guide the light impulses from source to destination. Optical Fiber provides a very large bandwidth data rates. Based on its requirements and needs, Networks communication are implemented as oCopper oOptical Fiber oWireless (Signal are propagated over the air)

Glass Fiber Structure The core vary its dimensions either the fiber is single or multimode. Light enter into the core and its cladding along the fiber The Cladding surronds or cover the core and is designed to prevent light loss from the fiber. Since the light can only travel in one direction over the optical cable, two fibers are required to support full duplex operations

Ray Light explanation Typically, the core size on Multiple Fiber are large enough so that, multiple light ray can enter to the core at different angles along the fiber. Multimode fiber employ Light Emitting Diodes (LEDs) with its proper angles to represent the transmitted data as bits along the media. Due the light enters the fiber at different angles, it takes different amount of time to travel down the fiber, and it may become confuse at the receiver side. This effect known as modal dispersion, limit the length of multimode fiber segments.

Ray Light explanation In Single Fiber, the core is so tiny that only one light ray which is perpendicular to the cable may be propagate along. Single Fiber employs a single Ray of Light as source generator to propagate the signals, because the laser is uni- directional and travels along the center of the fiber.

Single mode vs. Multimode Fibers Single-ModeMultimode Small core Less dispersion Carry a single ray of light, usually generated from a laser. Employ for long distance applications (100Km) Uses as Backbone and distances of several thousands meters. Larger core than single mode cable. Allows greater dispersion and therefore, loss of signal. Used for shorter distance application, but shorter than single-mode (up to 2Km) It uses LED source that generates differtes angles along cable. Often uses in LANs or small distances such as campus networks.

Waveguide calculation of Fiber Mode Here is fiber mode calculation based on Waveguide Calculation by Fiber Optics for Sale Company (USA) V number determines the numbers of guided modes. When V number is smaller than only one mode can be guided by the fiber, this is called single mode fiber. When V Numer is larger than severals modes can be guided by the fiber. As higer V number as larger number of modes, this is called Multimode Fiber

Multimode Fibers is more complex The multimode fiber keeps the same structure as single mode unlike the sieze of the core glass is bigger. Refractive index profile in multimode fibers The x (axes )shows fiber raduis The y (axes ) shows refractive index The core usually has a refractive index n1 = 1.48 The cladding has a refractive index n2 = 1.06 This is called Step-index fiber

Snews Law - Total Internal Reflection Snews Law describe the relation between the angles of incidents and refractions. When the Light Ray pass from a higher index material to a lower index material, light refraction occurs. When light incidents at interface between the core and the cladding has differents angles some power are reflacting back and some power enter into the cladding As the angle is increases larger than the target no more light enter into the Cladding layer and all the light reflect back into the core. This is called Total Internal Reflection. Core Cladding

Optical Fiber manufacturer Generally it consists on 2 steps by Glass Fiber preform Fiber Manufacturing Process 1st Step a preform is made and it has quite exactly the same proportion core as the cladding material. 2nd Step the preform pass through a monitor to deploy the final fiber into a drum to be storage and distributed.

Special fiber drawing tower Optical Implementation Technology offers by Yangtze Optical Fibre and Cable Company Ltd. (YOFC) a Chinese company established in May Reference a347-9afb3bec0dcb&comContentId=279b108f-7f a347- 9afb3bec0dcb&comp_stats=comp-FrontComContent_list html a347-9afb3bec0dcb&comContentId=279b108f-7f a347- 9afb3bec0dcb&comp_stats=comp-FrontComContent_list html

Nowadays, Optical Fibers connects the world under the sea and over the land Basically all digital communications travels via fiber. A single fiber can carry more communications than the biggest copper cable. Optical Fibers Applications

Telecommunications | Internet | Fiber at Home Video Streaming | Data Centers | Computer Networks Video and Audio Military | Governments | Airports |Hospital Intelligent | Public transportations Everywhere

Conclusion Optical Fiber = Optical + Fiber At Speed of Light Single Mode Fiber provides higher data rates speed and more distance than Single Mode Single Mode uses a single Ray of Light while Multimode Fiber employ Light Emitting Diodes (LEDs) to propagate the signal. At present, the fiber application might be infinite, however a deep analysis and design is recommended before implement a network.

Reference [1] Yangtze Optical Fibre and Cable Company Ltd. (YOFC) a347-9afb3bec0dcb&comContentId=279b108f-7f a347- 9afb3bec0dcb&comp_stats=comp-FrontComContent_list html [2] CISCO Networking Academy Program CCNA 1 and 2 book, 3rd Edition, Indianapolis – CISCO press, [3] About Optical Fiber, link: [4] Eugene Hecht – Optics, International Edition, Pearson Education

Thank you Kiitos Tack