Compact resonant electro-optic modulator using randomness of a photonic crystal waveguide

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Random photonic crystals offer unique light-manipulating properties.
• Controlling light confinement in disordered photonic structures is challenging.
• Previous attempts at device applications using random photonic crystals have limitations.

Purpose of the Study:

• To fabricate and demonstrate an electro-optic modulator based on random photonic crystal waveguides.
• To investigate methods for controlling light confinement within random photonic crystal structures.
• To achieve high Q-factor resonances and GHz-range electro-optic modulation.

Main Methods:

• Fabrication of a random photonic crystal waveguide with a narrowed section (W0.98) between wider sections (W1.05).
• Experimental measurement of the transmittance spectrum to determine the Q-factor.
• Numerical simulations to analyze light confinement and predict optimal design parameters.
• Integration of a p-i-n structure for electro-optic modulation.

Main Results:

• Achieved an ultra-high Q-factor of 2.4 × 10^5 in the W0.98 waveguide.
• Experimental yield rate for the high-Q confined mode exceeded 80% with optimized design.
• Demonstrated GHz electro-optic modulation due to predictable light confinement.
• Successfully controlled light confinement by restricting the area influenced by randomness.

Conclusions:

• Random photonic crystal waveguides can be effectively utilized for device applications by controlling the disordered region.
• The demonstrated electro-optic modulator exhibits high performance (ultra-high Q, GHz modulation).
• This approach provides a predictable method for light confinement in random photonic structures, paving the way for novel optical devices.