Fabrication of submillimeter-radius optical waveguide bends with anisotropic and isotropic wet chemical etchants

Wet chemical etchants suitable for making GaAs/AlGaAs single-mode optical waveguide bends with radii as low as 300 mu m for excess bend losses of 1 dB/90 degrees and propagation losses as low as 1 dB/cm at lambda =1.5 mu m are described. Additional bend losses due to modal mismatch resulting from etchant anisotropy are investigated, and it is shown that in many cases such anisotropy does not limit bend performance. >