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Envelope Making and Phase Encoding via External Modulation and Their Applications to Optical Fiber Secure Communications |
Yan Sen-lin |
The Department of Physics, Nanjing Xiaozhuang College, Nanjing 210017, China |
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Abstract Theoretical models of envelope making and phase making of optical fiber chaotic secure communication are studied by coupling the chaotic encoding multiple-quantum-well laser systems and an optical fiber channel. Effects of the self-phase modulation of optical fiber and optical amplifier number are analyzed. The modulation and demodulation quality is analyzed and an encoding formula is demonstrated. A phase controller can be used to reduce the effect of nonlinear phase shift of fiber on the synchronization and demodulation. Finally, envelope making with a bit rate of 0.2Gbit/s and phase masking with a bit rate of 0.05Gbit/s are simulated in long-haul optical fiber secure communications at wavelength 1.55μm. The systems have good secure performances.
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Received: 29 January 2007
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