SELECTIVE MOMBE GROWTH OF INP-BASED WAVEGUIDE LASER BUTT-JOINTS/

Selective metal organic molecular beam epitaxy regrowth of InP/GaInAsP passive optical waveguide structures was studied to accomplish butt c oupling to an active laser waveguide. Selective deposition of the pass ive waveguide layer stack around a masked laser mesa was performed at a growth temperature of 485 degrees C. The influence of the native oxi de desorption process of the V/III-ratio during growth and of a slight undercut etching was investigated. Uniform waveguide deposition was s uccessfully achieved even at the edges of the laser mesa, specifically in the vicinity of the active layers. The lateral growth rate was red uced to approximately 20% of the vertical rate and enhanced growth nea r the edge of the mask was completely suppressed. The high quality of the implemented butt-joint was demonstrated on Fabry-Perot lasers comp rising an active and a butt coupled passive waveguide section. An incr ease of the threshold current by only 25% for a 980 mu m long passive section as compared with a laser without a passive section was obtaine d. (C) 1998 Elsevier Science B.V. All rights reserved.