1.55 µm GaAs/GaNAsSb/GaAs optical waveguides grown by radio frequency nitrogen plasma-assisted molecular beam epitaxy

We demonstrate a 1.55 μm GaAsGaNAsSbGaAs optical waveguide grown by molecular beam epitaxy as an alternative to the AlGaAsGaAs system. The 0.4-μm -thick GaNAsSb guiding layer contains ∼3.5% of N and 9% of Sb, resulting in optical band gap of 0.88 eV. The refractive index of the GaNAsSb layer was measured from 800 to 1700 nm. The GaNAsSb layer has a refractive index value of 3.42 at 1.55 μm wavelength. The propagation loss measured using the Fabry-Ṕrot resonance method was found to be affected by nitrogen-related defect absorption.