Browsing by Author "DAI, LK"

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EFFECT OF POSITION-DEPENDENT TIME CONSTANT ON PHOTOREFRACTIVE 2-WAVE MIXING
(1992-09-01)
DAI, LK
;
GU, C
;
YEH, P
;
光電工程學系
;
Department of Photonics
The effect of a position-dependent time constant on nondegenerate photorefractive two-wave mixing is analyzed. For codirectional two-wave mixing the results indicate that the bandwidth of the two-wave-mixing gain decreases when the medium becomes lossy and that the photorefractive phase shift depends on the loss of the medium. In contradirectional two-wave mixing the total local intensity strongly depends on the coupling even if the medium is lossless. Thus the bandwidth is dependent on the energy coupling.
INSTABILITIES IN COUPLED PHOTOREFRACTIVE RING CAVITIES AND SELF-PUMPED PHASE CONJUGATORS
(1992-02-01)
DAI, LK
;
GOU, YS
;
GU, C
;
YEH, P
;
光電工程學系
In the preceding paper, we used the mean-field approximation to formulate the time evolution equations for two coupled unidirectional photorefractive ring resonators. Linear stability analysis based upon the steady-state solutions of the mean-field equations showed that the coupled system may become unstable in the unstable off- and steady-state operation regimes. In this paper, we investigate the temporal behavior and nonlinear dynamics of the coupled system. The results indicate that the coupled system exhibits self-pulsation and chaos in the unstable off-state and steady-state operation regimes. The instability is explained in terms of the competition between the nonlinear gain and loss. Numerical results of the transient equations are presented and discussed. The coupling between unidirectional ring resonators is extended to explain the instability in self-pumped phase conjugators.
INSTABILITIES IN COUPLED PHOTOREFRACTIVE RING CAVITIES AND SELF-PUMPED PHASE CONJUGATORS .1. MEAN-FIELD MODEL AND LINEAR-STABILITY ANALYSIS
(1992-01-01)
DAI, LK
;
GOU, YS
;
GU, C
;
YEH, P
;
光電工程學系
We investigate the temporal instabilities of mode intensities in two coupled unidirectional photorefractive ring resonators. The first resonator is driven by an external laser beam via photorefractive two-wave mixing. The internal oscillating beam is then employed to drive the second ring resonator. The second ring resonator provides a nonlinear loss mechanism for the coupled system. Complete spatial-temporal equations for describing the coupled system are derived and mean-field approximation is employed to simplify the transient analysis. The results of linear stability analysis indicate that the coupled system exhibits instability in the off-state and steady-state operation. The instability is explained in terms of competition between nonlinear gain and loss. The results are presented and discussed.
PHOTOREFRACTIVE MODE-COUPLING BETWEEN 2 UNIDIRECTIONAL RING OSCILLATORS
(1991-09-01)
DAI, LK
;
GOU, YS
;
YEH, P
;
GU, C
;
光電工程學系
We consider the coupling between two photorefractive unidirectional ring resonators. The first resonator is driven by an external laser beam via photorefractive two-wave mixing. The internal oscillating beam is then employed to drive the second ring resonator via the same mechanism. Closed form solutions for the oscillation intensities and frequencies are given, and their numerical results are presented and discussed. PACS: 42.65