InGaP χ⁽²⁾ integrated photonics platform for broadband, ultra-efficient nonlinear conversion and entangled photon...

Area of Science:

• Photonics and optical engineering.
• Quantum optics and quantum information science.
• Materials science for optical applications.

Background:

• Nonlinear optics is crucial for advancements in science and technology.
• Progress in nonlinear optics relies on developing materials with enhanced optical nonlinearity.
• Existing technologies in the telecommunication C band have limitations in nonlinear optical efficiency.

Purpose of the Study:

• To demonstrate an indium gallium phosphide (InGaP) integrated photonics platform.
• To achieve broadband and ultra-efficient second-order nonlinear optical effects.
• To develop an ultra-bright, broadband time-energy entangled photon source.

Main Methods:

• Fabrication of InGaP nanophotonic waveguides.
• Characterization of second-harmonic generation (SHG) efficiency at 1.55 μm.
• Generation and analysis of time-energy entangled photon pairs.

Main Results:

• Achieved normalized SHG efficiency of 128,000%/W/cm², nearly two orders of magnitude higher than state-of-the-art in the C band.
• Realized an ultra-bright, broadband entangled photon source with a pair generation rate of 97 GHz/mW and 115 nm bandwidth.
• Demonstrated high coincidence-to-accidental counts ratio (CAR > 10⁴) and two-photon interference visibility (>98%) for the entangled photon source.

Conclusions:

• The InGaP platform offers unprecedented efficiency for second-order nonlinear optics.
• The developed entangled photon source is suitable for demanding quantum applications.
• This InGaP nonlinear photonics platform has significant potential for quantum networking, optical signal processing, and non-classical light generation.