Post on 03-May-2018
Optical Multiplexing and Optical Multiplexing and DemultiplexingDemultiplexing
Brian SchulteBrian SchulteAhmed AlsinanAhmed Alsinan
AbstractAbstract
Optical multiplexing (and demultiplexing) Optical multiplexing (and demultiplexing) allows for sending multiple signals through allows for sending multiple signals through a single medium as well as for a single medium as well as for bidirectional use of that medium.bidirectional use of that medium.
Optical Time Domain Multiplexing (OTDM)Optical Time Domain Multiplexing (OTDM) Wavelength-Division Multiplexing (WDM)Wavelength-Division Multiplexing (WDM)
HistoryHistory Multiplexing and DemultiplexingMultiplexing and Demultiplexing
When did it start? When did it start?
HistoryHistory Western Union problemWestern Union problem
Thomas Edison:Thomas Edison: Wavelength strengthWavelength strength PolarityPolarity
Western Union Western Union electrical-mechanical multiplexing device electrical-mechanical multiplexing device
8 messages in 19138 messages in 1913 72 messages in 193672 messages in 1936
HistoryHistory Data Transmission Speeds Data Transmission Speeds
Characters Per Minute (CPM) Characters Per Minute (CPM)
Words Per Minute (WPM) Words Per Minute (WPM) 5 characters and space5 characters and space
Bits Per Second (bps) Bits Per Second (bps) 1950s 1950s 1200 bps 1200 bps Currently Currently 10 Gbps10 Gbps
HistoryHistory
Multiplexing Devices Development:Multiplexing Devices Development: Telegraph lines utilized DCTelegraph lines utilized DC Vacuum Tubes allowed AC in 1930s Vacuum Tubes allowed AC in 1930s Transistors replaced Vacuum Tubes in1960sTransistors replaced Vacuum Tubes in1960s Integrated CircuitsIntegrated Circuits
ApplicationsApplications
Optical Multiplexing Fiber Optic CableOptical Multiplexing Fiber Optic Cable
long distance communication at high bandwidthslong distance communication at high bandwidths
Useful for Fiber Optic Sensors Useful for Fiber Optic Sensors Sensors Sensors multiplexed into a single fibermultiplexed into a single fiber
Optical MultiplexingOptical Multiplexing
Optical Time-Division MultiplexingOptical Time-Division Multiplexing Based on Time-Division MultiplexingBased on Time-Division Multiplexing
Wavelength-Division Multiplexing Wavelength-Division Multiplexing Based on Frequency-Division Multiplexing of Based on Frequency-Division Multiplexing of
radio wavesradio waves
Time-Division MultiplexingTime-Division Multiplexing Transmitting digitized data over one mediumTransmitting digitized data over one medium
Wires or optical fibers Wires or optical fibers Pulses representing bits from different time slots Pulses representing bits from different time slots
Two Types:Two Types: Synchronous TDMSynchronous TDM Asynchronous TDMAsynchronous TDM
Synchronous TDMSynchronous TDM Accepts input in a round-robin fashion
Transmits data in a never ending pattern
Popular – Line & Sources as much bandwidth Popular – Line & Sources as much bandwidth Examples: T-1 and ISDN telephone lines SONET (Synchronous Optical NETwork)
Asynchronous TDMAsynchronous TDM Accepts the incoming data streams and creates a frame
containing only the data to be transmitted
Good for low bandwidth lines
Transmits only data from active workstations
Examples: used for LANs
Optical Time Division Multiplexing Optical Time Division Multiplexing (OTDM)(OTDM)
OTDM is accomplished by creating phase delays OTDM is accomplished by creating phase delays each signal together but with differing phase each signal together but with differing phase delaysdelays
Frequency-Division Multiplexing Frequency-Division Multiplexing (FDM)(FDM)
All signals are sent All signals are sent simultaneously, simultaneously, each assigned its each assigned its own frequencyown frequency
Using filters all Using filters all signals can be signals can be retrievedretrieved
Wavelength-Division Multiplexing Wavelength-Division Multiplexing (WDM)(WDM)
WDM is the combining of light by using WDM is the combining of light by using different wavelengthsdifferent wavelengths
Grating MultiplexerGrating Multiplexer
Lens focuses all Lens focuses all signals to the same signals to the same pointpoint
Grating reflects all Grating reflects all signals into one signalsignals into one signal
Grating MultiplexerGrating Multiplexer
Reflection off of Reflection off of grating is dependent grating is dependent on incident angle, on incident angle, order, and wavelengthorder, and wavelength
d(sinθi + sinθo) = mλ
Grating MultiplexerGrating Multiplexer Multiplexer is Multiplexer is
designed such that designed such that each each λλ and and θθii are are related related
Results in one signal Results in one signal that can then be that can then be coupled into a fiber coupled into a fiber optic cableoptic cable
Fabry-Perot MultiplexerFabry-Perot Multiplexer
Separates based on Separates based on wavelength = demuxwavelength = demux
Can be reversed for Can be reversed for multiplexermultiplexer