POLARIZATION ROTATION IN SEMICONDUCTOR BENDING WAVE-GUIDES - A COUPLED-MODE THEORY FORMULATION

A theoretical model for the bending waveguide polarization rotator has been developed based on the full-vectorial wave equations and the cou pled-mode theory. Calculation results from this model are found to agr ee favorably with measurement data reported in literature. It is found that the polarization conversion efficiency of this device hinges on the degree of asymmetry of the cross-sectional field profile with resp ect to both the x- and y-axes, Sensitivity analysis, furthermore, reve aled that the device characteristics are strongly dependent on the wav eguide geometry, in particular, the sidewall tilt angle and the amount of over-etch of the ridge waveguide, Finally, it is also found that t he bending waveguide polarization rotator is virtually wavelength inde pendent, making it suitable for wavelength division multiplexing (WDM) applications.