Enhanced optical bistability in slotted photonic crystal structure for microwave frequency generation

Area of Science:

• Photonics
• Nanotechnology
• Optoelectronics

Background:

• Photonic crystal nanocavities are crucial for integrated optics.
• Optical bistability and self-pulsing are key phenomena for signal processing.
• Silicon nanocrystals offer unique nonlinear optical properties.

Purpose of the Study:

• To design and analyze a silicon nanocrystal/SiO2 embedded slotted photonic crystal nanocavity.
• To investigate optical bistability and self-pulsing for microwave signal generation.
• To evaluate the device's performance and fabrication tolerance.

Main Methods:

• Theoretical modeling incorporating Kerr nonlinearity, two-photon absorption, and free carrier effects.
• Precise width modulation of the nanocavity.
• Simulation of optical bistability and self-pulsing oscillations.

Main Results:

• Achieved ultra-high quality factor (Q) and low modal volume.
• Demonstrated low threshold power for optical bistability (-20 pm detuning).
• Generated microwave frequencies at 21.34 GHz via self-pulsing, with a second harmonic observed.
• Confirmed performance robustness against fabrication variations (up to 20% in air hole positions).

Conclusions:

• The proposed silicon nanocrystal photonic crystal nanocavity is feasible for low-power, high-frequency integrated photonic applications.
• The design shows significant potential for microwave signal generation.
• Width modulation is an effective technique for controlling nonlinear optical phenomena in nanocavities.