Design of strip-loaded weak-guiding multimode interferencestructure for an optical router

We introduce a new multimode interference structure that can be used as an integrated optical router. This structure is based on the existence of a first cross state in weakly guiding multimode waveguides. Such a cross image, not expected by the self-imaging technique, is tested by rigorous modal analysis as well as the nonmodal beam propagation method. We show that the quality of this image could be enhanced by strip loading the multimode section of the structure. Making use of this image, we propose a new optical router based on the large nonlinearity associated with the blockaded reservoir and quantum-well electron transfer structure     

Stable and noniterative bidirectional beam propagation method

We present a family of bidirectional beam propagation methods based on the application of Pade approximants to the square-root expressions appearing in the transition operator. We show that the numerical instability associated with the use of real Pade primes can be removed by using branch-cut rotation of the square-root operator     

An optimized InGaAsP/InP polarization converter employing asymmetric rib waveguides

In this paper, we report on the design of a compact (/spl ap/ 226 /spl mu/m) on-chip InGaAsP/InP polarization converter based on an asymmetric rib waveguide. Our theoretical analysis demonstrates that the device displays a conversion efficiency of < -25 dB (> 99.68% power conversion between orthogonal polarization) at 1550-nm wavelength with a nearly flat response over the optical C band. Regarding fabrication tolerances, we predict that the most sensitive design parameter is the waveguide width as the conversion efficiency drops to 10 dB for a deviation of /spl plusmn/ 0.1 /spl mu/m from the optimized value.     

The Design and Optimization of an Ion-Exchanged Polarization Converter Using a Genetic Algorithm

In this work, a genetic algorithm is used for the optimization of the design parameters of an integrated optical polarization converter on a glass substrate. The algorithm is applied to find the minimum possible length for the converter. The required asymmetry for the structure is realized with the aid of a cleaving process following the ion-exchange process. Simulation results show the possibility of realizing such a low-cost integrated converter. The obtained results demonstrate the importance of using such an algorithm in integrated optics problems where several design parameters such as the geometrical dimensions, the temperature, and the time duration are to be optimized.     

The application of complex Pade approximants to reflection atoptical waveguide facets

We demonstrate that the numerical instabilities associated with the use of the standard real Pade approximation for the reflection operator can be avoided through either a complex Pade expression or a branch-cut rotation in the complex plane