Bistability and all-optical flip-flop with active microring resonator

Area of Science:

• Photonics and Optical Engineering
• Nonlinear Optics
• Integrated Optics

Background:

• Microring resonators are key components in integrated photonics.
• Nonlinearity and losses in microring resonators can lead to complex behaviors.
• Active gain media can compensate for resonator losses.

Purpose of the Study:

• To investigate the bistability of an active nonlinear microring resonator.
• To design a flip-flop circuit utilizing the bistable properties of the microring resonator.
• To analyze the impact of gain on the resonator's switching characteristics.

Main Methods:

• Utilizing an Er-doped gain medium to compensate for nonlinear and linear losses.
• Employing both analytical and numerical methods to solve light propagation.
• Analyzing hysteresis loops to confirm bistability.
• Designing a set-reset flip-flop by incorporating feedback mechanisms.

Main Results:

• The active nonlinear microring resonator exhibits clear bistability, confirmed by hysteresis loops.
• Gain from the Er-doped medium reduces the required bias power for switching.
• The system functions as a bistable optical switch.
• A functional set-reset flip-flop was realized based on the microring's bistability.

Conclusions:

• Bistability in active nonlinear microring resonators is achievable and useful for optical switching.
• Gain compensation is effective in reducing switching power requirements.
• Pulse duration exceeding field buildup time is critical for reliable flip-flop operation (approx. 2 ps).