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Time-bin modulated polarization-entangled biphotons from cavity-enhanced down-conversion

Christopher E. Kuklewicz·Franco N. C. Wong·Jeffrey H. Shapiro
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Abstract

We have generated a new type of biphoton state by cavity-enhanced down-conversion in a type-II phase-matched, periodically-poled KTiOPO_4 (PPKTP) crystal. By introducing a weak intracavity birefringence, the polarization-entangled output was modulated between the singlet and triplet states according to the arrival-time difference of the signal and idler photons. This cavity-enhanced biphoton source is spectrally bright, yielding a single-mode fiber-coupled coincidence rate of 0.7 pairs/s per mW of pump power per MHz of down-conversion bandwidth. Its novel biphoton behavior may be utilized in sensitive measurements of weak intracavity birefringence.

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Christopher E. Kuklewicz, Franco N. C. Wong, Jeffrey H. Shapiro. 2006-05-10. Time-bin modulated polarization-entangled biphotons from cavity-enhanced down-conversion. https://doi.org/10.1103/physrevlett.97.223601

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