Bistable random momentum transfer in a linear on-chip resonator

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nonlinear Optics

Background:

• Optical switches and signal bifurcation typically depend on nonlinear material responses.
• Chaotic modes in microdisks show broadband transfer but their transient responses and signal output are less understood.
• Previous research explored chaotic modes in deformed cavities, yielding random analog signal outputs between 0 and 1.

Purpose of the Study:

• To demonstrate linear temporal bifurcation responses in a passive multimode microresonator.
• To investigate the conversion of periodic clock signals into binary outputs using coupled chaotic and whispering gallery modes (WGMs).
• To analyze the performance of a novel optical switch based on silicon nanocrystal-perturbed microring resonators.

Main Methods:

• Perturbing multimode microring resonators with densely packed silicon nanocrystals on the waveguide surface to build chaotic states.
• Utilizing in vivo measurements to analyze the transient response and output characteristics of the microresonator.
• Coupling bus waveguide modes to chaotic modes and subsequently to stable whispering gallery modes (WGMs).

Main Results:

• Achieved a passive linear temporal bifurcation response in a microresonator system.
• Observed a "digitized" output where signals exclusively populated around 0 and 1 intensity levels.
• Demonstrated a binary pathway with high contrast (exceeding 12.3 dB), high data rates (up to 10^7 bits per second), and a 20 dB dynamic range.

Conclusions:

• The developed passive device enables real-time conversion of periodic clock signals into binary outputs.
• The strong coupling between chaotic modes and WGMs in silicon nanocrystal-perturbed microring resonators facilitates high-contrast binary signal generation.
• This approach offers a promising route for low-power, high-speed optical switching and signal processing applications.