Propagation loss in GaN-based ridge waveguides

GaN ridge waveguides were fabricated by selective area growth in an organometallic vapor phase epitaxial system. The growth enhancement on a 3.5 mum wide exposed channel versus the masked area width was measured. The propagation losses of a series of GaN multimode waveguides, with different widths, were measured by the outscattering technique at lambda=488 nm. The internal optical loss of the GaN ridge waveguide was found to be alpha(int)similar to4.45 cm(-1). Sidewall scattering loss (alpha(scat)) and the additional optical loss due to metal electrodes were also measured. The fabricated waveguides may be a basic component for integrated optic circuits. (C) 2004 American Institute of Physics.