A new fabrication method of deeply buried corrugated waveguides is presente
d. It uses a direct bonding process and allows us to make efficient grating
couplers in waveguides. The efficiency of the grating is enhanced by enclo
sing air in its grooves during the fabrication process, A demonstrator base
d on a waveguide produced by ion exchange has been fabricated and tested. T
heoretical and experimental results are compared.