Ge<i>x</i>Si1−<i>x</i> optical directional coupler

Abstract

We have fabricated and characterized the first GexSi1−x optical directional couplers. These structures were fabricated from GexSi1−x grown by rapid thermal processing chemical vapor deposition. The average attenuation of single, straight waveguide sections was 3.3 dB/cm at a wavelength of 1.52 μm. For the directional couplers, the coupling coefficient was 3.9 cm−1 for a waveguide separation of 1.5 μm.