Analytical modal analysis of bent slot waveguides.

We analyze modal properties of dielectric optical bent slot waveguides by using the multilayer formulation of the well-known classical analytical model of bent waveguides based on the Bessel-Hankel functions. Unlike the previously studied approximate model based on the Airy functions, this model is valid for all values of bend radii. The present approach allows quick and accurate computations of propagation constants, mode profiles, and field-power densities for the 2D bent slot waveguides with very small radii. Using this model we characterize the optimal slot position inside the bent core to maximize the field enhancement in the slot. Such modal analysis is quite useful for the design of devices involving bent slot waveguides. Moreover the results obtained by the present 2D rigorous analytical model can also be used for benchmarking other numerical tools.