Fully tunable and switchable coupler for photonic routing in quantum detection and modulation.

Area of Science:

• Photonics
• Quantum Optics
• Optical Engineering

Background:

• Photonic routing is crucial for optical applications but faces development challenges.
• Efficient and controllable photonic devices are needed for advanced quantum technologies.

Purpose of the Study:

• To report a novel $2\times 2$ photonic coupler with electronically switchable splitting ratios.
• To demonstrate its utility in quantum information processing and quantum optics.

Main Methods:

• Utilized a Mach-Zehnder interferometer in a dual-wavelength configuration.
• Implemented low-voltage electronic control for real-time phase locking and switching.
• Achieved sub-nanosecond switching between arbitrary coupling regimes.

Main Results:

• Demonstrated a switchable $2\times 2$ photonic coupler with 10 GHz bandwidth and tens of nanoseconds latency.
• Achieved arbitrary splitting ratios (0:100 to 100:0) with a 26 dB extinction ratio over a 1.3 THz optical bandwidth.
• Showcased stable, sub-nanosecond switching at the single-photon level, enabling balanced time-multiplexed devices and photonic temporal qudit state preparation.

Conclusions:

• The developed photonic coupler provides unprecedented control over light splitting for quantum applications.
• Its stable, single-photon level operation makes it a valuable component for quantum information processing and quantum optics research.