Abstract
We report measurements of the nonlinearity profile of thermally poled low-loss germanosilicate films deposited on fused-silica substrates by PECVD, of interest as potential electro-optic devices. The profiles of films grown and poled under various conditions all exhibit a sharp peak ~0.5 microm beneath the anode surface, followed by a weaker pedestal of approximately constant amplitude down to a depth of 13-16 microm, without the sign reversal typical of poled undoped fused silica. These features suggest that during poling, the films significantly slow down the injection of positive ions into the structure. After local optimization, we demonstrate a record peak nonlinear coefficient of ~1.6 pm/V, approximately twice as strong as the highest reliable value reported in thermally poled fused silica glass, a significant improvement that was qualitatively expected from the presence of Ge.
Highlights
Poled glass has been an active area of research over the last few years because of the prospect of using this nonlinear material for integrated electro-optic phase and amplitude modulators or parametric oscillators.[1]
After optimizing the poling time, we investigated the effect of the germane flow rate on the induced nonlinearity profile
We have reported measurements of the nonlinearity spatial profile of thermally poled germanosilicate films deposited on fused-silica substrates by plasma-enhanced chemical vapor deposition (PECVD)
Summary
Poled glass has been an active area of research over the last few years because of the prospect of using this nonlinear material for integrated electro-optic phase and amplitude modulators or parametric oscillators.[1]. Glasses, including the fact that the Ge-doped layer blocks diffusion of the positive ions from the anode surface during poling and that the space charge distribution inside the poled region exhibits a dipolar structure within the first micron below the anode surface, followed by a neutral region from ~1 μm to ~12 μm, which is followed by a weaker negatively charged region up to a total depth of ~16 μm These findings are quite important especially for the optimization of the overlap between the optical mode of an electro-optic device utilizing poled germanosilicate films and the induced nonlinear region
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call