Browsing by Author "Juang, C"

Now showing 1 - 13 of 13

A synchronization scheme using self-pulsating laser diodes in optical chaotic communication
(2000-03-01)
Juang, C
;
Hwang, TM
;
Juang, J
;
Lin, WW
;
應用數學系
A synchronization scheme using self-pulsating laser diodes in optical chaotic communication is proposed. Optical chaotic light can be obtained by injecting a sinusoidal electronic signal into a self-pulsating laser diode. To synchronize between two identical chaotic systems with different initial conditions, a drive and response system model is constructed according to Pecora and Carroll's theory. Synchronization can be achieved for optical simplex and duplex transmissions provided that the conditional Lyapunov exponents for the drive and response systems are all negative. This approach offers a key step toward realizing optical chaotic modulation and demodulation.
Chaotic behavior of hole mixing tunneling in asymmetric coupled quantum wells
(1997-02-01)
Juang, C
;
Tsai, CB
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
Coherent oscillatory motion of hole mixing tunneling in asymmetric coupled quantum well structures collapses if the heavy hole state in the first well is aligned with the light hole state in the second well under a significant in-plane vector k(parallel to). The tunneling probability obtained by the time-dependent Schrodinger operator with the Luttinger Hamiltonian in the oscillation collapse region is shown to be a chaotic time series using the simplex projection method. This effect is attributed to the nonlinear interaction of mixing tunnelings between HH to the LH state in the first well and HH to the LH state in the second well. (C) 1997 Elsevier Science Ltd.
Chaotic behavior of hole mixing tunneling in asymmetric coupled quantum wells
(1997-02-01)
Juang, C
;
Tsai, CB
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
Coherent oscillatory motion of hole mixing tunneling in asymmetric coupled quantum well structures collapses if the heavy hole state in the first well is aligned with the light hole state in the second well under a significant in-plane vector k(parallel to). The tunneling probability obtained by the time-dependent Schrodinger operator with the Luttinger Hamiltonian in the oscillation collapse region is shown to be a chaotic time series using the simplex projection method. This effect is attributed to the nonlinear interaction of mixing tunnelings between HH to the LH state in the first well and HH to the LH state in the second well. (C) 1997 Elsevier Science Ltd.
Chaotic behaviors of bistable laser diodes and its application in synchronization of optical communication
(2001-10-01)
Wang, WC
;
Hwang, TM
;
Juang, C
;
Juang, J
;
Liu, CY
Period-doubling routes to chaos behavior in bistable laser diodes is examined numerically, An external sinusoidal electronic drive is injected to generate chaotic light output. Phase portrait, Poincare map, bifurcation diagram, and Lyapunov exponent are then calculated to assert the existence of chaos. Furthermore, according to Pecora and Carroll's theory, a drive-response system is constructed by using the bistable laser diodes to mask the sinusoidal electronic signal with chaotic light. Synchronization can be achieved for optical simplex and duplex transmissions using bistable laser diodes. The proposed synchronization scheme between two separate chaotic systems provides a key step toward optical chaotic communication.
Charge oscillations in coupled quantum wells
(1997-04-01)
Juang, C
;
Tsai, CB
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
A study of charge oscillations due to electron- and hole-coherent, and mixing tunnelling in coupled quantum well structures is given. The time-dependent picture of coherent tunnelling of an electron and hole wave packet is obtained by the application of the time-development operator of the time-depsndent Schrodinger equation, and the time-dependent Schrodinger equation with the Luttinger Hamiltonian. Detailed physical mechanisms involving resonant coherent tunnelling on electrons, valence-band mixing effects on heavy- and light-hole tunnelling, spatial and mixing multiple tunnelling effects, in coupled quantum wells are described.
Charge oscillations in coupled quantum wells
(1997-04-01)
Juang, C
;
Tsai, CB
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
A study of charge oscillations due to electron- and hole-coherent, and mixing tunnelling in coupled quantum well structures is given. The time-dependent picture of coherent tunnelling of an electron and hole wave packet is obtained by the application of the time-development operator of the time-depsndent Schrodinger equation, and the time-dependent Schrodinger equation with the Luttinger Hamiltonian. Detailed physical mechanisms involving resonant coherent tunnelling on electrons, valence-band mixing effects on heavy- and light-hole tunnelling, spatial and mixing multiple tunnelling effects, in coupled quantum wells are described.
Controlling chaotic behavior of heavy to light hole mixing tunneling by external electric fields
(1997-08-01)
Juang, C
;
Wang, JY
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
Oscillatory and chaotic motion of heavy to light hole mixing tunneling in asymmetric coupled quantum-well structures can be controlled by an external electric field. Chaotic behavior occurs if the heavy-hole state in the first well is aligned with the light-hole state in the second well under a significant in-plane vector k(parallel to). Oscillatory motion is recovered if the external electric field disrupts the alignment between the heavy-hole state in the first well and the light-hole state in the second well.
FM detection from an optical chaotic carrier
(2001-07-01)
Huang, ST
;
Hwang, TM
;
Juang, C
;
Juang, J
;
Lin, WW
To synchronize two identical chaotic systems with different initial conditions, a drive and response system model is constructed according to Pecora and Carroll's theory. The drive and response systems become asymptotically synchronized if an FM signal is added to the drive system. The FM signal can be detected when the drive and response systems are strongly coupled.
Multiple tunneling and chaos in asymmetrically coupled quantum wells
(1999-11-01)
Juang, C
;
Lee, GY
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
Oscillatory and chaotic motion of heavy to light hole mixing tunneling in asymmetrically coupled quantum well structures is determined by two competing processes: HHa to LHa and HHa to LHb. Chaotic behavior occurs if the two processes ale compatible. Oscillatory motion is recovered if one process is dominant. The effects of barrier width, external field, and in-plane wave factor kit on each process are addressed.
Nonlinear dynamics of self-pulsating laser diodes under external drive
(1999-10-01)
Juang, C
;
Chen, MR
;
Juang, J
;
應用數學系
;
Department of Applied Mathematics
A self-pulsating laser diode under external drive shows the nonlinear dynamical effects of two competing frequencies. One can establish a route to chaos by increasing the modulation current. However, when the modulation frequency is varied, the chaotic state is suddenly destroyed at the harmonic frequencies of the self-pulsating frequency. This approach therefore offers a simple chaotic light source for possible optical chaotic communication. (C) 1999 Optical Society of America.
Optical chaotic AM demodulation by asymptotic synchronization
(2000-02-01)
Juang, C
;
Hwang, TM
;
Juang, J
;
Lin, WW
;
應用數學系
Synchronization between two identical chaotic systems (drive and response) with different initial conditions can be achieved provided that the conditional Lyapunov exponents are all negative. Adding an AM signal to the drive system, the two systems become asymptotically synchronized. The AM signal can be recovered by utilizing the property of the asymptotic synchronization. Chaotic AM noise is present as a direct result of the chaotic AM demodulation. Signal-to-chaotic-AM-noise ratio is calculated as a function of the signal amplitude.
Optoelectronic delayed-feedback and chaos in quantum-well laser diodes
(2001-05-15)
Juang, C
;
Huang, CC
;
Hwang, TM
;
Juang, J
;
Lin, WW
Electronic-controlled route to chaos in a quantum-well laser diode is carried out by a delayed-feedback technique. By introducing an extra delayed-feedback control term cS(n)(t - tau), chaotic light output can be achieved at relatively low bias and small modulation depth. Bifurcation diagram, Poincare map, and Lyapunov exponents suggests quasi-periodicity route to chaos. (C) 2001 Elsevier Science B.V. All rights reserved.
Subcarrier multiplexing by chaotic multitone modulation
(2003-10-01)
Juang, C
;
Huang, ST
;
Liu, CY
;
Wang, WC
;
Hwang, TM
Subcarrier multiplexing by chaotic multitone modulation is investigated. Optical chaotic light can be achieved by injecting multiple subcarriers into a self-pulsating laser diode. Synchronization between two identical chaotic systems (drive and response) can be implemented provided that the conditional Lyapunov exponents are all negative. By adding amplitude modulation (AM) signals to each subcarrier, the two systems become asymptotically synchronized. The AM signals in each subcarrier can be recovered by the introduction of a filtering process where the Lyapunov exponent of the synchronized error function matches the cutoff frequency of a first order low pass filter.