multiplexing presentation
DESCRIPTION
multiplexingTRANSCRIPT
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Optical Multiplexing and DemultiplexingBrian SchulteAhmed Alsinan
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AbstractOptical multiplexing (and demultiplexing) allows for sending multiple signals through a single medium as well as for bidirectional use of that medium.
Optical Time Domain Multiplexing (OTDM)Wavelength-Division Multiplexing (WDM)
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HistoryMultiplexing and DemultiplexingWhen did it start?
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HistoryTelegraphy1800s
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History1894Baudots multiplex telegraph
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HistoryWestern Union problem
Thomas Edison: Wavelength strengthPolarity
Western Union electrical-mechanical multiplexing device 8 messages in 191372 messages in 1936
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HistoryData Transmission Speeds
Characters Per Minute (CPM)
Words Per Minute (WPM) 5 characters and space
Bits Per Second (bps) 1950s 1200 bpsCurrently 10 Gbps
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HistoryMultiplexing Devices Development:Telegraph lines utilized DCVacuum Tubes allowed AC in 1930s Transistors replaced Vacuum Tubes in1960s Integrated Circuits
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ApplicationsOptical Multiplexing Fiber Optic Cable
long distance communication at high bandwidths
Useful for Fiber Optic Sensors Sensors multiplexed into a single fiber
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Optical MultiplexingOptical Time-Division MultiplexingBased on Time-Division Multiplexing
Wavelength-Division Multiplexing Based on Frequency-Division Multiplexing of radio waves
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Time-Division MultiplexingTransmitting digitized data over one mediumWires or optical fibers Pulses representing bits from different time slots
Two Types:Synchronous TDMAsynchronous TDM
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Synchronous TDMAccepts input in a round-robin fashion Transmits data in a never ending patternPopular Line & Sources as much bandwidth Examples: T-1 and ISDN telephone linesSONET (Synchronous Optical NETwork)
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Asynchronous TDMAccepts the incoming data streams and creates a frame containing only the data to be transmittedGood for low bandwidth linesTransmits only data from active workstationsExamples: used for LANs
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Optical Time Division Multiplexing (OTDM)OTDM is accomplished by creating phase delays each signal together but with differing phase delays
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Frequency-Division Multiplexing (FDM)
All signals are sent simultaneously, each assigned its own frequencyUsing filters all signals can be retrieved
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Wavelength-Division Multiplexing (WDM)
WDM is the combining of light by using different wavelengths
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Grating Multiplexer
Lens focuses all signals to the same point
Grating reflects all signals into one signal
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Grating Multiplexer
Reflection off of grating is dependent on incident angle, order, and wavelength
d(sini + sino) = m
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Grating MultiplexerMultiplexer is designed such that each and i are related
Results in one signal that can then be coupled into a fiber optic cable
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Fabry-Perot Filter
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Fabry-Perot Multiplexer
Separates based on wavelength = demux
Can be reversed for multiplexer
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ConclusionHistory Applications Optical Time Division MultiplexingWavelength-Division MultiplexingGrating MultiplexerFabry-Perot Multiplexer
Bandwidth is limited because each switching must occur at a rate fast enough for each line to have a continuous conversation. Even though all the incident angles are different, the reflection is the same because the wavelengths are different in such a way to be related through d(sini + sino) = m.Multiplexer is designed such that each wavelength and incident angle are related such that all the signals are reflected into one signal
Two mirrors with a set of standing waves between them.