Power Absorption Efficiency in Superconducting Box-Shaped Optical Waveguides

A very sensitive superconducting traveling wave photodetector made of a modified box-shaped waveguide, which includes two high index layers and an active superconducting layer, is studied. The optical propagation constants and the power absorption efficiency for guided modes are determined using the finite element method; the results show that by acting only on the waveguide geometry, different confinement regimes of the light in the absorption superconducting layer can be achieved and optimized.