Direct generation of polarization-entangled photon pairs in a poled fiber

Eric Y. Zhu*, Zhiyuan Tang, Li Qian, Lukas G. Helt, Marco Liscidini, J. E. Sipe, Costantino Corbari, Albert Canagasabey, Morten Ibsen, Peter G. Kazansky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)


We experimentally demonstrate the direct generation of polarization- entangled photon pairs in an optical fiber at room temperature by exploiting type-II phase-matched spontaneous parametric down-conversion. A second-order nonlinearity is artificially induced in the 17-cm-long weakly birefringent step-index fiber through the process of thermal poling, and quasi-phase-matching allows for the generation of entangled photons in the 1.5-micron telecom band when the fiber is pumped at 775 nm. A greater-than 80 1 coincidence-to- accidental ratio is achieved, limited mainly by multiphoton pair generation. Without the need to subtract accidentals or to compensate for walk-off, the raw two-photon interference visibility is found to be better than 95%, and violation of Bell's inequality is observed by more than 18 standard deviations. This makes for a truly alignment-free, plug-and-play source of polarization-entangled photon pairs.

Original languageEnglish
Article number213902
Pages (from-to)1-5
Number of pages5
JournalPhysical Review Letters
Issue number21
Publication statusPublished - 21 May 2012
Externally publishedYes


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