Efficient wavelength selective soliton switching using fiber gratings in single and cascaded nonlinear optical loop mirrors

The soliton switching performance of the nonlinear optical loop mirror (NOLM) with inserted fiber Bragg grating is examined numerically in this paper. The relationships between various grating designs to the self-switching characteristics of the device are presented, including cases where low switching powers and rapid switching transitions are observed. Particular attention is paid to the bandpass nonlinear switching behavior of the NOLM, introduced with the inclusion of the grating. This analysis is extended to consider a novel cascaded loop configuration, in which the gratings in each loop are tuned to a different wavelength. A three-channel simulation of a two-loop cascade is presented with a discussion on the suitability of the NOLM device to wavelength-division-multiplexing (WDM) applications.