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

Properties of C
2
F
6
(freon 116) reactive ion-beam etching (RIBE) of LiNbO
3
, Ti-indiffused LiNbO
3
, and sputter-deposited Nb
2
O
5
film on LiNbO
3
are reported. A maximum differential etching ratio of approximately 5:1 has been measured for LiNbO
3
and the AZ 1350B Shipley photoresist. We have used this etching technique to fabricate diffraction gratings on both Ti-indiffused LiNbO
3
and Nb
2
O
5
- LiNbO
3
waveguides with measured throughput efficiencies in excess of 85 percent.