We demonstrate the highest-quality Bragg gratings reported to date in chalcogenide glass rib waveguides, both in strength and apodization. A modified Sagnac interferometer is employed to write gratings in As2S3-based rib waveguides, achieving an induced refractive index modulation of the order of 10<sup>−2</sup> and a grating transmission rejection of more than 30 dB. We obtain good agreement between experimental and theoretical results based on a transfer-matrix formulation for multilayer optical structures. In addition, we report fabrication of phase-shifted Bragg gratings, as well as an investigation of the role of birefringence, higher-order modes, and aging. Finally, grating growth dynamics are investigated by in situ monitoring during writing.
© 2006 Optical Society of America
Original Manuscript: July 22, 2005
Revised Manuscript: February 15, 2006
Manuscript Accepted: February 15, 2006
Mehrdad Shokooh-Saremi, Vahid G. Ta'eed, Neil J. Baker, Ian C. M. Littler, David J. Moss, Benjamin J. Eggleton, Yinlan Ruan, and Barry Luther-Davies, "High-performance Bragg gratings in chalcogenide rib waveguides written with a modified Sagnac interferometer," J. Opt. Soc. Am. B 23, 1323-1331 (2006)