Abstract
We report nonlinear optical characterization of cm-long polycrystalline silicon (poly-Si) waveguides at telecom wavelengths. Laser post-processing of lithographically-patterned amorphous silicon deposited on silica-on-silicon substrates provides low-loss poly-Si waveguides with surface-tension-shaped boundaries. Achieving optical losses as low as 4 dB cm-1 enabled us to demonstrate effects of self-phase modulation (SPM) and two-photon absorption (TPA). Analysis of the spectral broadening and nonlinear losses with numerical modeling reveals the best fit values of the Kerr coefficient n2=4.5×10-18 m W-1 and TPA coefficient βTPA=9.0×10-12 m2 W-1, which are within the range reported for crystalline silicon. On-chip low-loss poly-Si paves the way for flexible integration of nonlinear components in multi-layered photonic systems.
Highlights
Over the last two decades, polycrystalline silicon has attracted growing interest as a material with great prospects for the convergence of electronics and photonics
Laser-induced residual tensile strains remain uniform along the polycrystalline silicon (poly-Si) waveguides, due to the thermal steady-state conditions ensured by the constant scan speeds and powers during laser processing, and were observed to be stable at room temperatures for several months, without causing any physical deformation
Our results have shown that laser post-processing of amorphous silicon (a-Si) deposited on planar substrates is a promising approach to obtain poly-Si waveguides with optical losses low enough to observe third-order nonlinear effects, such as self-phase modulation (SPM), four-wave mixing (FWM) and cross-phase modulation (XPM)
Summary
Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. OZAN AKTAS,1,* STUART J. MACFARQUHAR,1 SWE Z. OO,2 ANTULIO TARAZONA,1 HAROLD M. H. CHONG,2,3 AND ANNA C. PEACOCK1
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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
