C2F6reactive ion-beam etching of LiNbO3and Nb2O5and their application to optical waveguides

Properties of C2F6(freon 116) reactive ion-beam etching (RIBE) of LiNbO3, Ti-indiffused LiNbO3, and sputter-deposited Nb2O5film on LiNbO3are reported. A maximum differential etching ratio of approximately 5:1 has been measured for LiNbO3and the AZ 1350B Shipley photoresist. We have used this etching technique to fabricate diffraction gratings on both Ti-indiffused LiNbO3and Nb2O5- LiNbO3waveguides with measured throughput efficiencies in excess of 85 percent.