A photonic integrated continuous-travelling-wave parametric amplifier

Area of Science:

• Photonics and Optical Engineering
• Semiconductor Devices
• Materials Science

Background:

• Optical signal amplification is crucial, typically relying on rare-earth-doped fibers or III-V semiconductors.
• Parametric amplification using Kerr nonlinearity in optical fibers offers an alternative, enabling applications like noiseless amplification and signal regeneration.
• Previous photonic integrated circuit (PIC) demonstrations required pulsed lasers, limiting practical applications; bulk periodically poled lithium niobate (PPLN) achieved continuous-wave gain but lacked silicon integration.

Purpose of the Study:

• To demonstrate a photonic-integrated-circuit-based travelling-wave optical parametric amplifier (OPA) with net signal gain in the continuous-wave (CW) regime.
• To overcome the limitations of pulsed lasers in previous PIC-based parametric gain demonstrations.
• To integrate continuous-wave parametric gain onto a silicon photonic chip.

Main Methods:

• Utilized ultralow-loss, dispersion-engineered, metre-long silicon nitride (Si3N4) photonic integrated circuits.
• Fabricated the device on a compact 5x5 mm^2 silicon chip.
• Achieved travelling-wave parametric amplification in the continuous-wave regime.

Main Results:

• Demonstrated a continuous parametric gain of 12 dB in the telecommunication C band.
• The achieved gain exceeded on-chip propagation loss and fiber-chip-fiber coupling losses.
• The device operates within a compact footprint on a silicon chip.

Conclusions:

• This work presents the first PIC-based CW travelling-wave OPA with net signal gain.
• The developed parametric amplifiers offer lithographically controlled gain spectrum, compact size, and resilience to feedback.
• The technology holds potential for applications from visible to mid-infrared, outside conventional rare-earth amplification bands, and offers quantum-limited performance.