Abstract

Nonlinear directional waveguide couplers have attracted a great deal of attention as major candidates for the creation of ultrafast all-optical switches. Such a device utilizes light tunneling between two optical waveguides placed in a close proximity to each other, where light is switched between the waveguides at the distance called the coupling length. At high input powers, intensity-dependent change of the refractive index through optical nonlinearity creates detuning between the waveguides which can suppress power transfer between the coupler ports, such that light remains in the input waveguide. However, a conventional coupler can perform only switching of signals with rather limited spectral bandw idth, because the coupling length depends on optical frequency resulting in separation of different frequency components between the waveguides as shown in Figs. 1(a) and 1(c).

© 2007 IEEE