Fabricating low-loss hollow optical waveguides via amorphous silicon bonding using dilute KOH solvent

This work explicates a method for fabricating a hollow optical waveguide. Dilute KOH solvent was used to bond two omni-directional reflector (ODR) Si wafers to an amorphous Si thin film on the top of a Si wafer. The resultant bonding interface is very thin, with a thickness that is close to that of a SiO/sub 2/ layer in the ODR substrate. Therefore, the far field image reveals that light is strongly confined in the hollow optical waveguide.