Quantum decoherence of dark pulses in optical microresonators

Area of Science:

• Nonlinear optics
• Quantum optics
• Materials science

Background:

• Dissipative Kerr solitons (DKSs) are crucial for compact frequency comb sources.
• Quantum fluctuations limit the timing stability and performance of DKSs.
• Advancements in device technology enable probing quantum properties of DKSs.

Purpose of the Study:

• Investigate quantum decoherence in dark pulses within normal-dispersion microresonators.
• Characterize the quantum-limited coherence of dark pulses.
• Compare the coherence of dark pulses with bright solitons.

Main Methods:

• Utilized an AlGaAs-on-insulator microresonator with large material nonlinearity.
• Observed quantum decoherence of dark pulses directly.
• Employed stochastic photon injection to resolve dynamical processes.
• Performed phase correlation measurements.

Main Results:

• Direct observation of quantum decoherence in dark pulses.
• Achieved comb spacing uniformity better than 1.2 × 10^-16 (normalized to optical carrier frequencies).
• Demonstrated superior quantum-limited coherence of dark pulses compared to bright solitons.

Conclusions:

• Dark pulses in AlGaAs microresonators exhibit enhanced quantum-limited coherence.
• This work provides critical assessment and guidelines for coherence engineering of chip-scale optical frequency combs.