frequency [ghz]
Post on 31-Dec-2015
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Frequency [GHz]
Time [ns]
Mea
sure
d ou
tput
v [
mV
]V
(t -
)
[mV
]
Periodic Quasi-periodic Chaotic
PS
D
[dB
]V(t) [mV]
High Speed Chaos Generated in an Opto-Electronic OscillatorKristine Callan, Lucas Illing, and Daniel J. GauthierDuke University, Department of Physics, the Fitzpatrick Center for Photonics and Communication Systems, and the Center for Nonlinear and Complex Systems Durham, North Carolina 27708 USA
Possible Applications
Observed dynamics
•Time-delayed feedback occurs in many systems •Important at high speeds (time it takes signals to propagate through device ~ time scale of fluctuations)•Simple nonlinear devices can show complex dynamics•We report on a single time-delayed chaotic device
Outlook
Chaotic Transmitter
Object
Correlator
Receiver
•Intrusion detection system•Envisioned system would use network of devices that transmit and receive chaotic signals•Dynamics of system incorporates received signals high sensitivity •Complex signals low probability of detection
•Chaotic Radar•Current systems use periodic signals to gauge distance to object•Proposed system would send chaotic signal, receive it, and gauge distance from correlation of transmitted and received signal
•Dynamics change with change in feedback strength, VBias, and length of time delay
•Observed multistability and hysterisis effects
Single chaotic device
Optical Signal
Electric Signal
•Light passes through optical fiber to Mach Zehnder Modulator (MZM)
•Nonlinear input/output function of MZM modulates light
•Detector converts light intensity to RF signal
•Electrical signal amplified and fed back to serve as input for MZM
•Antenna could be placed at output to transmit signal
Nonlinearity
Pou
tput /
Pin
put
VBias [V]
•Characterize single device dynamics
•Characterize dynamics of two coupled devices
•Model behavior of network of coupled devices
LaserLaser ModulatorModulator DetectorDetector
Driv
erD
river VBiasVBias
CouplerCouplerOutputOutput
Nonlinearity
dd
Introduction
Support•US Army Research Office (grant #W911NF-05-1-0228)
Time delay
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