Soliton Research at the Lightwave Soliton Research at the Lightwave Communication Systems Communication Systems

LaboratoryLaboratory

Ken Demarest

Department of Electrical Engineering & Computer ScienceUniversity of Kansas

SummarySummary

• Introduction to optical solitons

• The KU soliton generator

• The KU recirculating loop

• Preliminary soliton transmission results

• Summary and suggestion for future work

Optical SolitonsOptical Solitons

An optical soliton is a short, high-amplitude an optical pulse that does not spread as it propagates

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t

t

tOrdinary PulesSoliton Pules

t

fiber

fiber

Inpu

t

Inpu

t

Out

put

Out

put

Linear, Dispersive FiberLinear, Dispersive Fiber

.

Inte

nsit

y

Inte

nsit

yTime

Frequency

Lengt

h

Lengt

h

Kerr Effect and ChirpKerr Effect and Chirp

Amplitude Profile Kerr Phase Instantaneous Frequency

Front Back

t

t

t

Nonlinear, Nondispersive fiberNonlinear, Nondispersive fiber

.

Inte

nsity

Inte

nsity

Time

Nonlinear Fiber with Positive Nonlinear Fiber with Positive DispersionDispersion

.

Frequency

Inte

nsit

y

Inte

nsit

yTime

Fundamental SolitonFundamental Soliton

.

Inte

nsity

Inte

nsity

Time

Soliton-based optical fiber Soliton-based optical fiber transmissiontransmission

Achieved error free distances in single-channel and WDM

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Title:soliton2.psCreator:XV Version 3.00 Rev: 3/30/93 - by John BradleyPreview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

Three Types of Soliton Three Types of Soliton GeneratorsGenerators

1. Soliton laser based on mode-locking

2. Electroabsorption Modulator-based soliton generators

3. LiNbO3 Mach-Zehnder Modulator-based soliton generators

Mach-Zehnder Soliton Mach-Zehnder Soliton GeneratorGenerator

Amplitude ModulationAmplitude Modulation

Pulse CompressionPulse Compression

Structure and OperationStructure and OperationTitle:/tmp/xfig-fig015248Creator:fig2devPreview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

KU Soliton GeneratorKU Soliton Generator

Uncompressed pulses

Compressed pulses

Mearsured Pulse CompressionMearsured Pulse Compression

Soliton Source: OutputSoliton Source: Output

Soliton Train Data Encoded Soliton Sequence

20GHz Time/polarization 20GHz Time/polarization Division Multiplexed Soliton Division Multiplexed Soliton

TrainTrain

PM fiber

Incident LightPolarization of

Soliton Generator For WDMSoliton Generator For WDM

Recirculating LoopRecirculating Loop

KU Recirculating Loop TestsetKU Recirculating Loop Testset

OC48 Rate Transmission OC48 Rate Transmission EmulationEmulation

Standard Fiber

75 km: Error Free

600 km: Error Free(BER<2*10-13)

1050 km: BER=2*10-10

1350 km: BER=3*10-7

20 ps/divTransmitter

4*35 km

6*35 km

Launch power: 8 dBm -2.5 dBm

Measured, Near-Soliton Measured, Near-Soliton CharacteristicsCharacteristics

Future WorkFuture Work

1. Long-distance 10 Gb/s or time/polarization-division-multiplexedsoliton transmission in alternating positive and negative dispersion fiber links.

2. 10 Gb/s or 20 Gb/s WDM transmission in dispersion- compensated standard fiber link with long amplifier spans.

3. Experimental demonstration of soliton control for all-optical networks.