Fast and slow light in zigzag microring resonator chains.

We analyze fast- and slow-light transmission in a zigzag microring resonator chain. In the superluminal case, a new light-transmission effect is found whereby the input optical pulse is reproduced in an almost-simultaneous manner at the various system outputs. When the input carrier is tuned to a different frequency, the system permits to slow down the propagating optical signal. Between these two extreme cases, the relative delay can be tuned within a broad range. We propose, and analyze numerically, a laser-array configuration for the stable operation of active devices.

Transmission bistability in a double-coupler fiber ring resonator.

The transmission bistability of a two-coupler nonlinear ring resonator is demonstrated and described by using a geometrical method that provides a qualitative understanding of the operation characteristics of the device. Results showing the influence of the coupling constants and the linear phase are presented.

Coupled-mode equations for nonlinear directional couplers.

We point out some inconsistencies in the usual coupledmode formulation employed to model the nonlinear behavior of symmetric directional couplers. In particular, we show that special care is required when neglecting some of the nonlinear terms in the equations.