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

Joshua Akin; Yunlei Zhao; Yuvraj Misra; A K M Naziul Haque; Kejie Fang

doi:10.1038/s41377-024-01653-5

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

Light Sci Appl. 2024 Oct 15;13(1):290. doi: 10.1038/s41377-024-01653-5.

Authors

Joshua Akin^#^{1

2}, Yunlei Zhao^#^{1

2}, Yuvraj Misra^{1

2}, A K M Naziul Haque^{1

2}, Kejie Fang^{3

4}

Affiliations

¹ Holonyak Micro and Nanotechnology Laboratory and Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
² Illinois Quantum Information Science and Technology Center, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
³ Holonyak Micro and Nanotechnology Laboratory and Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. [email protected].
⁴ Illinois Quantum Information Science and Technology Center, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. [email protected].

^# Contributed equally.

Abstract

Nonlinear optics plays an important role in many areas of science and technology. The advance of nonlinear optics is empowered by the discovery and utilization of materials with growing optical nonlinearity. Here we demonstrate an indium gallium phosphide (InGaP) integrated photonics platform for broadband, ultra-efficient second-order nonlinear optics. The InGaP nanophotonic waveguide enables second-harmonic generation with a normalized efficiency of 128, 000%/W/cm² at 1.55 μm pump wavelength, nearly two orders of magnitude higher than the state of the art in the telecommunication C band. Further, we realize an ultra-bright, broadband time-energy entangled photon source with a pair generation rate of 97 GHz/mW and a bandwidth of 115 nm centered at the telecommunication C band. The InGaP entangled photon source shows high coincidence-to-accidental counts ratio CAR > 10⁴ and two-photon interference visibility > 98%. The InGaP second-order nonlinear photonics platform will have wide-ranging implications for non-classical light generation, optical signal processing, and quantum networking.