OPTICAL LOSS MEASUREMENTS ON GAAS GAALAS SINGLE-MODE WAVE-GUIDE Y-JUNCTIONS AND WAVE-GUIDE BENDS/

The propagation losses in a GaAs/GaAlAs double heterostructure single- mode waveguide symmetrical Y-junctions have been measured as a functio n of the full angle alpha of the Y-junction. It was found that it was possible experimentally to identify whether the Y-junction waveguide w as single mode. The bending loss in bent waveguides, due to the change in the axial direction of the waveguide, was measured as a function o f the bending angle alpha/2. It was also experimentally confirmed that the bending loss was significantly reduced by increasing the lateral optical field confinement, i.e., by increasing the etch depth of the r ib waveguide.