Introduction To Optical Fiber Communication
Introduction to OpticalFiber CommunicationDr. Mohammad FaisalDepartment of EEE, BUET
Communication ceiverMessageDestinationNoise,Interference,Delay DistortionFigure: Block diagram of a general communication system Transmission Media:BW RangeDistance can be coveredCu-wire: kHz:Coaxial Cable: MHzMicrowave Link: MHz ‒ GHzSatellite Channel: GHzOptical Fiber: THzCarrier frequency for Microwave Communication 1 GHz (Typical)for Optical fiber Communication 100 THz (10 14 Hz), 105 times larger thanthat of Microwave Communication2
EM Spectrum for Fiber-Optic Communication3
EM Spectrum for Fiber-Optic Communication4
Background Historical PerspectiveEarly civilizations have used mirrors, fire beacons or smoke signals forcommunication (to convey a single information, mainly warning purpose)Up to 18th century (even today): signaling lamps (traffic control, naval vessel,airport control tower), flags and different other semaphore devices.FlagSignaling LampFire BeaconThe Term “fiber optics” was first introduced by N.S. Kapany at London duringdeveloping “flexible fiberscope” in 1956 (claim)Charles Kao and Charles Hockham at Standard Terleocom Lab in Englandproposed optical fiber as comm channel in 1966. At that time fiber loss wasfound as 20 dB/km
BackgroundIn 1830s – Telegraphy, LightIs replaced by ElectricityUse: Morse Code, dot-dash(Digital), 10bpsIn 1876 – Telephone isinventedAnalog Electrical SignalElectrical Comm SystemIn 1966 – Optical FiberInitially fiber loss 1000 dB/kmGradually: 20 dB/km0.2 dB/kmEmergence of new technology6
Evolution of Lightwave System1st Generation Lightwave System:1970 1975, upto 1980Operated near 0.8 μmAttenuation (fiber loss) ( ) 1.0 dB/kmBit Rate 45 Mb/sRepeater spacing 10 kmGaAs Semiconductor Laser Diode was used2nd Generation Lightwave System:Became available commercially in 1980sOperated near 1.3 μmAttenuation (fiber loss) 0.5 dB/kmBit Rate 100 Mb/s (MMF), increased (up to GB/s) by SMFRepeater spacing 50 km (SMF)InGaAsP Semiconductor Laser Diode was used
Evolution of Lightwave System3rd Generation Lightwave System:Became available commercially in 1990Operated near 1.55 μm, Fiber Dispersion is high at thisrange for SMFAttenuation (fiber loss) 0.2 dB/kmBit Rate 2.5 Gb/sRepeater spacing 60 km, Electronic Repeaters (socoherent receivers used to increase bit rate)4th Generation Lightwave System:Became available after 1990 (around 1992)Operated near 1.55 μmAttenuation (fiber loss) 0.2 dB/kmBit Rate 10 Gb/s, Optical Amplification WDMTechnology System capacity is enhanced muchRepeater spacing: 60 80 kmBy 1996, large number of submarine lightwave systems were8deployed suing that technology
5th Generation Lightwave System:Starting from 2000Operated near 1.55 μm, (covering S, C, L bands: extended thewavelength range of WDM system)Attenuation (fiber loss) ( ) 0.2 dB/km, Dry fiber can be used:Low loss over 1.3 μm to 1.65 μm wavelength rangeBit Rate 10 Gb/s, 40 Gb/s, 1000s of WDM channels arepossible, Total capacity 100 Tb/s or moreEDFA, and Raman Amplifier can be usedRepeater spacing 60 km,Fiber-optic communication technology is around 35 yearsold. Started from around 1975, It has advanced rapidly. 1stgeneration started with capacity of 45 Mb/s, after 35 yearsthe capacity has jumped by a factor of more than 10,0009
10
Evolution of Lightwave SystemLow loss window for lightwave system at different stages
Evolution of Lightwave SystemIncrease of bit-rate distance product with time
Basic Principle of Optical Fiber CommunicationNon-electrical signal is converted into electricalsignal by transducer and the transmitter(modulator) converts it into proper formOE SourceE/O Converter: LED or LASER (for high speed)OE DetectorO/E Converter: Optoelectronic detector PINphotodiode or APD (for high speed)ReceiverFilter Amplifier, for Digital: Decision circuit13
A Typical Optical Fiber Communication SystemMessageSourceModulatorOpticalSourceLED orLASERdrive ber cablep-i-nphotodiode/APDReconstructedsignal atDestination14
Advantages and Disadvantages of OFCAdvantages: Huge Potential BW: 1013 to 1016 Hz Small Size and Weight: very small core dia 10 μm (SMF),(less than human hair, 20 to 180 μm), 50 μm (MMF) Electrical isolation: glass or plastic (no earth loop, no spark or short ckt) Immunity to interference and crosstalk: dielectric WG (no EMI, no RFI, notransient, not susceptible to lightning strikes) Signal Security: no significant radiation, not broadcasting like wireless Low loss: 0.2 dB/km, wide repeater spacing Robustness & flexibility: fiber cables have high tensile strength, compact,small bend radii System Reliability and ease of maintenance: life time 20-30yrs etc.Disadvantages: Huge Installation Cost but cost/capacity decreases15
Carrier frequency for Microwave Communication 1 GHz (Typical) 14for Optical fiber Communication 100 THz (10 Hz), 105 times larger than that of Microwave Communication 2 Message Source Transmitter Receiver Transmission Medium Message Destination Noise, Interference, Delay Distortion Figure: Block diagram of a general communication system
From the above-mentioned features of using optical fiber link as a transmitted media, it is proven that it is the best communication link. The following sections review the different components that constitute the optical fiber communication system, namely the optical transmitter,the optical fiber links and the optical receiver. II.
2.7 Fabrication of Optical Fiber 53 2.8 Drawing of Optical Fibers 54 2.9 Classification of Fiber Cables 57 2.10 The Selection of Fiber Cable 62 2.11 Installation Procedures 63 2.12 Performance of Optical Fiber Cables 64 2.12.1 Mini Bundle Cable 64 2.13 High Performance Optical Communications Cable 66 Problems 68 References 69 3.
1.2 General Optical Fiber Communication System Basic block diagram of optical fiber communication system consists of following important blocks. 1. Transmitter 2. Information channel 3. Receiver. Optical Fiber Communication 10EC72 .
Fiber optic collimators are components designed to collimate/focus light exiting a fiber to a desired optical beam. G&High powered fiber optic collimators offer 's SM h high reliability with low optical loss. Ideal for use in fiber sensors and fiber lasers. The fiber collimators are available in several single mode fiber types with operating .
2 Optical fiber communication technology 2-1 Optical communication principles and wavelength division multiplexing Within photonic technology there are modes such as the propagation of light through space, but this article discusses optical fiber communications utilizing optical fibers of glass materials with silicon oxide (SiO2) as the
A fiber optic communication system fulfills these requirements, hence most widely acception. 1.2 General Optical Fiber Communication System Basic block diagram of optical fiber communication system consists of following important blocks. 1. Transmitter 2. Information channel 3
Fiber optic communication systems use guided media (optical fiber) to transmit information superimposed on light from a transmitter to a receiver. Fig. 1 is a block diagram of the fiber optic communication system; it comprises a transmitter, channel (optical fiber), photo-detector and a receiver. The channel for
This project aims is how to build an optical fiber that transmit the signal from transmitter to receiver and what its components. The objective of this project: -Understand basic concepts of communication system. -Understand how the signal go throw the optical fiber. -Be familiar with parts of the optical fiber.
