Stress-induced vertical confinement of light in bulk GaAs and Si substrates

We propose a new waveguide structure that can be formed on bulk semiconductor substrates without requiring any epitaxial or separate cladding layers for vertical confinement of light. In the proposed structure, vertical confinement of light is achieved via a photoelastic effect in semiconductor induced by thin-film stress, and lateral confinement is obtained by a semiconductor mesa. We have carried out numerical analyses on the stress distribution, dielectric constant changes, and mode profiles at 1.3 μm or 1.55 μm wavelength in GaAs or Si mesas. The results show that the proposed structure can support vertical modes with the amount of stress that can be obtained from typical thin-film/semiconductor interfaces.