[OPTICAL REVIEW Vol. 7, No. 1 (2000) 83-88]

Effect of Material Response Time on Optical Bistability in Nonlinear Distributed Feedback Gratings

Kazuhiko OGUSU and Takashi KAMIZONO

Department of Electrical and Electronic Engineering, Shizuoka University, 3-5-1, Johoku, Hamamatsu, 432-8561 Japan

(Received July 28, 1999; Accepted October 14, 1999)

The dynamic behaviors of nonlinear periodic waveguides with a finite material response time have been investigated by numerically solving both the coupled-mode equations and Debye relaxation equation. When the response time of the nonlinearity is more than the transit time through the grating, a modulational instability is sufficiently suppressed and one can obtain optical bistability. Unlike a nonlinear Fabry-Perot resonator or ring resonators, overshoot in the transmission never takes place in the case of zero detuning. However, a relaxation (or damped) oscillation always takes place in the presence of detuning. It is also found that the switch-on time depends on the material response time and the switch-off time is almost independent of it.

Key words : nonlinear periodic waveguide, fiber Bragg grating, optical bistability, modulational instability, Kerr effect