Low-loss AlGaAs optical rectangular waveguides at 830 nm

Optical channel waveguides with rectangular cross section and losses less than 0.1 dB/cm at 830 nm have been fabricated in AlGaAs heterostructures grown by organometallic vapor phase epitaxy. The modal attenuation correlates with surface morphology for all waveguide widths and with sidewall roughness for narrow channels. Surface morphology and modal attenuation improve when a superlattice buffer layer is incorporated into the structure. The loss is also reduced when the arsenic source (arsine) is purified in-line.