Semiconductor waveguide source of counterpropagating twin photons.

Area of Science:

• Quantum optics
• Semiconductor device physics
• Integrated photonics

Background:

• Development of compact and efficient sources of entangled or twin photons is crucial for quantum information processing.
• Semiconductor-based sources offer potential for on-chip integration and scalability.
• Telecom wavelength operation is essential for leveraging existing fiber optic infrastructure.

Purpose of the Study:

• To experimentally demonstrate an integrated semiconductor source of counterpropagating twin photons operating in the telecom range.
• To characterize the properties of the emitted photon pairs, including their spectral linewidth and coincidence.
• To explore the potential of such sources for future guided-wave quantum devices.

Main Methods:

• Utilizing an Aluminum Gallium Arsenide (AlGaAs) waveguide.
• Pumping the waveguide with a laser beam to induce parametric down-conversion.
• Detecting and performing time-correlation measurements on the generated signal and idler photons.

Main Results:

• Successful generation of two counterpropagating, orthogonally polarized signal/idler guided modes.
• Emission of one average photon pair per pump pulse at room temperature from a 2 mm long waveguide.
• Achieved a spectral linewidth of 0.15 nm for the emitted photons.
• Confirmed the twin nature of the photons via time-correlation measurements.

Conclusions:

• An integrated semiconductor source of telecom-range counterpropagating twin photons has been experimentally demonstrated.
• The developed AlGaAs waveguide platform shows promise for on-chip quantum photon generation.
• This work establishes a foundation for novel guided-wave semiconductor quantum devices.