We demonstrate monolithic fabrication of tunable, waveguide embedded Bragg gratings (WBG) in lithium niobate by direct femtosecond laser writing. Complex refractive index modulation profiles such as chirped and multi periodic gratings are inscribed into the core volume of a circular, two-dimensional waveguide structure. The hybrid type-I/II design that consists of a type-II waveguide and a type-I multiscan grating exhibits low loss symmetric guiding of ordinary and extraordinary polarized modes and narrowband reflections in the c-band of optical communications. High bandwidth spectral tunability of more than a peak half width and nearly preserved electro{optic coefficients of r13 = 7:67pmV^-1 and r33 = 24:7pmV^-1 are realized.

Date Published: 13 March 2015
PDF: 8 pages
Proc. SPIE 9374, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics VIII, 937404 (13 March 2015); doi: 10.1117/12.2079871

Published in SPIE Proceedings Vol. 9374:
Advanced Fabrication Technologies for Micro/Nano Optics and Photonics VIII
Georg von Freymann; Winston V. Schoenfeld; Raymond C. Rumpf; Henry Helvajian, Editor(s)