Fabricating a hollow optical waveguide for optical communication applications

This work demonstrates a direct amorphous Si low-temperature wafer bonding technique to fabricate a semiconductor hollow waveguide with omni-directional reflectors for use in near infrared applications. The 2% dilute KOH solution was used to bond two ODR Si wafers with an amorphous Si thin film on the top of Si wafers. The resultant bonding interface is very thin, with a thickness that is close to that of the SiO₂ layer in the ODR substrate. Hence, the far-field image shows that light is strongly confined in the waveguides. The propagation loss was reduced to 1.0 ± 0.5 db/cm in the TE and TM modes, broadening the development of the semiconductor hollow waveguide with omni-directional reflectors for use in optical communication applications.