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Title: InGaP quantum nanophotonic integrated circuits with 1.5% nonlinearity-to-loss ratio

Optical nonlinearity plays a pivotal role in quantum information processing using photons, from heralded single-photon sources and coherent wavelength conversion to long-sought quantum repeaters. Despite the availability of strong dipole coupling to quantum emitters, achieving strong bulk optical nonlinearity is highly desirable. Here, we realize quantum nanophotonic integrated circuits in thin-film InGaP with, to our knowledge, a record-high ratio of1.5%<#comment/>between the single-photon nonlinear coupling rate (g/2π<#comment/>=11.2MHz) and cavity-photon loss rate. We demonstrate second-harmonic generation with an efficiency of71200±<#comment/>10300%<#comment/>/Win the InGaP photonic circuit and photon-pair generation via degenerate spontaneous parametric downconversion with an ultrahigh rate exceeding 27.5 MHz/µW—an order of magnitude improvement of the state of the art—and a large coincidence-to-accidental ratio up to1.4×<#comment/>104. Our work shows InGaP as a potentially transcending platform for quantum nonlinear optics and quantum information applications.

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Article No. 258
Optical Society of America
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National Science Foundation
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