Tunable delay line based on balanced coupled resonators cladded with VO₂ films.

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Tunable delay lines are crucial components in optical signal processing.
• Existing technologies often face limitations in response time, distortion, and tunability.

Purpose of the Study:

• To design and simulate a continuously tunable delay line with ultrafast response and low distortion.
• To leverage the photoinduced phase transition properties of vanadium dioxide (VO2) films.

Main Methods:

• Utilized a balanced side-coupled integrated spaced sequence of resonators.
• Incorporated phase change material VO2 films into the resonator structure.
• Performed simulations to evaluate delay, bandwidth, loss, and switching time.

Main Results:

• Achieved a continuously tunable delay of up to 80 picoseconds (ps).
• Demonstrated a 150 GHz bandwidth with only 10% broadening and a low delay loss of 0.087 dB/ps.
• Observed an ultrafast switching time of less than 0.6 ps due to the photoinduced phase transition of VO2.

Conclusions:

• The proposed VO2-based tunable delay line offers significant advantages for high-bit-rate all-optical processing systems.
• The device effectively compensates for group delay dispersion, enabling high-performance optical communication.