The various techniques that have been used to fabricate waveguides in GaAs/GaAkAs are reviewed; including p-n junction, carrier-concentration-reduction, heteroepitaxial growth, and strip-loading methods. The results of this survey show that it is possible to produce waveguides in GaAs/GaAkAs with losses less than 2 dB/cm for wavelengths ranging from 1.06 to 10.6μm. In some cases losses as low as 1 dB/cm have been observed.
Robert G. Hunsperger,
"Waveguide Fabrication Techniques In AlGaAs/GaAℓAs", Proc. SPIE 0517, Integrated Optical Circuit Engineering I, (29 January 1985); doi: 10.1117/12.945132; https://doi.org/10.1117/12.945132