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High nonlinear figure-of-merit amorphous silicon waveguides
J Matres1, G C Ballesteros, P Gautier
1Nanophotonics Technology Center, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022, Valencia, Spain. joamatab@ntc.upv.es
Optics Express
|March 14, 2013
Summary
Amorphous silicon waveguides show significantly lower nonlinear losses than silicon-on-insulator, offering a 7x higher figure of merit for nonlinear optics applications. This improvement stems from the absence of slow free-carrier effects.
Area of Science:
- Materials Science
- Photonics
- Nonlinear Optics
Background:
- Silicon photonics relies on understanding material nonlinearities.
- Silicon-on-insulator (SOI) suffers from nonlinear losses due to free-carrier effects.
- Amorphous silicon (a-Si) is an alternative material for photonic devices.
Purpose of the Study:
- To investigate and quantify the nonlinear optical response of amorphous silicon waveguides.
- To compare the nonlinear performance of a-Si with traditional SOI.
- To determine the suitability of a-Si for low-loss nonlinear photonic applications.
Main Methods:
- Nonlinear coefficient (γ) measurement using four-wave-mixing (real part).
- Nonlinear loss characterization via peak power-dependent measurements (imaginary part).
- Time-resolved measurements and simulations for carrier dynamics analysis.
Main Results:
- Amorphous silicon waveguides exhibit a nonlinear figure of merit 7 times higher than SOI.
- The nonlinear coefficient γ was accurately determined for a-Si.
- Absence of slow free-carrier effects in a-Si, unlike the ns lifetimes observed in SOI.
Conclusions:
- Amorphous silicon presents a superior nonlinear optical performance compared to SOI.
- The suppression of free-carrier effects makes a-Si highly promising for nonlinear photonic integrated circuits.
- a-Si waveguides offer enhanced efficiency and reduced signal degradation in nonlinear optical processes.
