Browsing by Author "WANG, TY"

Now showing 1 - 4 of 4

SELF-INDUCED TRANSPARENCY IN A DISPERSIVE AND NONLINEAR KERR HOST MEDIUM
(1991-10-15)
WANG, TY
;
CHI, S
;
光電工程學系
;
電信研究中心
;
Department of Photonics
A steady-state solution that describes pulse propagation in inhomogeneously broadening two-level atoms embedded in a dispersive and nonlinear Kerr lossless host medium has been found. The solution is of an unchirped hyperbolic-secant form with a linear spatial phase delay. The features of the solution are (i) the group velocity, the amplitude, and the width of the pulse are uniquely determined for given parameters of the medium and the carrier frequency; (ii) the group velocity is independent of the density of the resonant atoms; and (iii) the solution can exist in the positive dispersion region.
STEADY-STATE PULSE-PROPAGATION IN AN AMPLIFYING MEDIUM EMBEDDED IN A DISPERSIVE AND NONLINEAR KERR HOST
(1992-05-15)
CHI, S
;
WANG, TY
;
光電工程學系
;
電信研究中心
;
Department of Photonics
We have found the steady-state solutions in a homogeneously broadened two-level amplifying medium embedded in a dispersive and nonlinear Kerr host medium. The solution is of an unchirped hyperbolic-secant form. There are two kinds of solutions, pi-pulse and 2-pi-pulse. The pi-pulse propagates with the same velocity as that in the host, but the 2-pi-pulse propagates faster than that in the host. Each of the pi-pulse and 2-pi-pulse solutions has a unique amplitude and pulse width which are determined by the parameters of the medium. The solutions exist only when the dipole moment of the laser medium and the parameters of the host medium satisfy a specific relationship, which can be realized by choosing a proper dispersion of the host medium in the negative region.
THE OPTICAL SOLITON TRANSMISSION AMPLIFIED BY BIDIRECTIONAL RAMAN PUMPS WITH NONCONSTANT DEPLETION
(1991-08-01)
WEN, SF
;
WANG, TY
;
CHI, S
;
光電工程學系
;
電信研究中心
A numerical method is proposed to solve the coupled equations between the soliton and bidirectional Raman pump waves. The pump depletion due to the soliton is obtained without using the constant depletion approximation. With this method, the soliton propagation in a Raman-pumped fiber can be solved accurately. It is found that the constant depletion approximation is valid at a small depletion rate, which requires low soliton power (or long pulsewidth), small material loss, and a short-pump period. In a periodically Raman-pumped fiber, there exists a stable signal energy, which is very sensitive to the pump intensity. We have also studied the stability of the soliton propagation with nonconstant pump depletion. It is found that the stability predicted by nonconstant depletion (NCD) and constant depletion assumption (CDA) are generally different.
THEORY OF SELF-INDUCED TRANSPARENCY IN A KERR HOST MEDIUM BEYOND THE SLOWLY-VARYING-ENVELOPE APPROXIMATION
(1993-04-01)
CHI, SE
;
WANG, TY
;
WEN, SF
;
電信研究中心
;
光電工程研究所
The self-induced transparency in the Kerr host medium has been studied beyond the slowly-varying-envelope approximation. An analytic solution is obtained. There exists a hyperbolic-secant soliton whose power, pulse width, group velocity, and propagation constant are uniquely determined for given parameters of the medium. The reductions of the group velocities of the solitons by the self-induced-transparency effect in the resonant medium with homogeneous and inhomogeneous broadening are also studied. It is found that there is negative dispersion induced by the self-induced transparency, which is not predicted by the theory with the slowly-varying-envelope approximation. The amount of the induced dispersion is determined by the total dispersion of the system required to be compensated by the Kerr effect. Numerical examples of the self-induced transparency in an erbium-doped fiber are shown. In a typical erbium-doped fiber, the soliton solution has not been found because the inhomogeneous-broadening linewidth of the medium is too large.