Hybrid scattering in periodic waveguides

Abstract

A mechanism for frequency generation which can occur in waveguide distributed‐feedback lasers on anisotropic substrates is discussed. The proposed mechanism is a hybrid Bragg scattering between oppositely travelling waves with orthogonal polarizations. It explains the frequency spectrum observed in the preceding letter, which occurs as a result of the simultaneous presence of two coupled‐wave phenomena: mode conversion due to the anisotropic substrate, and backward Bragg scattering due to the periodic waveguide structure.