Ultralow power continuous-wave frequency conversion in hydrogenated amorphous silicon waveguides.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Semiconductor Physics

Background:

• Nonlinear optical processes are crucial for optical signal processing and wavelength conversion.
• Silicon photonics has shown promise, but materials with higher nonlinearities are sought for improved performance.
• Hydrogenated amorphous silicon (a-Si:H) presents an alternative material with potentially enhanced nonlinear optical properties.

Purpose of the Study:

• To demonstrate and characterize wavelength conversion in hydrogenated amorphous silicon (a-Si:H) using nonlinear parametric processes.
• To determine the nonlinear optical properties of a-Si:H, specifically its nonlinear refractive index.
• To assess the potential of a-Si:H for high-speed telecommunication applications.

Main Methods:

• Utilizing nonlinear parametric processes, specifically four-wave mixing (FWM), for wavelength conversion.
• Measuring conversion efficiency and bandwidth under specific pump power and data rate conditions.
• Characterizing the nonlinear refractive index (n2) of a-Si:H through experimental measurements.

Main Results:

• Achieved a maximum wavelength conversion efficiency of -13 dB at telecommunication data rates (10 GHz).
• Observed significant conversion bandwidths up to 150 nm (20 THz) in the continuous-wave regime.
• Determined a nonlinear refractive index (n2) of 7.43×10(-13) cm(2)/W for a-Si:H, which is approximately ten times higher than that of single crystal silicon.

Conclusions:

• Hydrogenated amorphous silicon (a-Si:H) is a highly effective material for efficient wavelength conversion.
• The enhanced nonlinear refractive index of a-Si:H makes it a promising candidate for next-generation silicon photonics and optical communication systems.
• The demonstrated performance at telecommunication data rates highlights the practical applicability of a-Si:H in optical signal processing.