High resistivity, low loss InGaAlAs/InP optical waveguides grown by low-temperature MBE

The authors present a study of material properties relevant to optical waveguides of MBE (molecular-beam epitaxy) grown InGaAlAs ( gamma g=1.06 mu m) layers lattice-matched to InP. In particular, the impact of the substrate temperature was investigated. MBE growth of In0.52Ga0.18Al0.30As ( gamma g=1.06 mu m) layers in the temperature range of 400-450 degrees C was demonstrated to give high-quality optical waveguides which not only exhibit low propagation losses of well below 2 dB/cm at gamma =1.55 mu m but also high resistivity of >104 Omega -cm. The refractive index of In0.52Ga0.18Al0.30As was estimated to be 3.207+or-0.03 at gamma =1.55 mu m.