Photon pair generation in hydrogenated amorphous silicon microring resonators.

Area of Science:

• Materials Science
• Quantum Optics
• Photonics

Background:

• Amorphous silicon (a-Si:H) is a promising material for integrated photonics.
• Microring resonators are key components for generating correlated photon pairs.
• Understanding nonlinear optical properties is crucial for optimizing device performance.

Purpose of the Study:

• To determine the nonlinear Kerr coefficient of a-Si:H.
• To investigate power-dependent optical loss in a-Si:H microrings.
• To theoretically compare a-Si:H and crystalline silicon (c-Si) microring pair sources.

Main Methods:

• Photon pair generation using a continuous-wave (CW) pump in a-Si:H microrings.
• Measurement of the Q factor as a function of coupled power.
• Theoretical modeling of photon pair generation rates in a-Si:H and c-Si microrings.

Main Results:

• The Kerr coefficient of a-Si:H was measured to be 3.73 ± 0.25 × 10^-17 m²/W.
• Optical loss in a-Si:H microrings scales linearly with power, ruling out two-photon absorption as the primary loss mechanism.
• The high Kerr coefficient of a-Si:H is most beneficial for microrings with Q factors below 10³.

Conclusions:

• Amorphous silicon exhibits a high Kerr coefficient suitable for nonlinear photonic applications.
• Linear power-dependent loss in a-Si:H microrings necessitates careful device design.
• For high-Q factor devices, the photon pair generation rate is significantly limited by first-order loss, favoring lower-Q designs for this material.