Simple method of generating and distributing frequency-entangled qudits

Rui Bo Jin, Ryosuke Shimizu, Mikio Fujiwara, Masahiro Takeoka, Ryota Wakabayashi, Taro Yamashita, Shigehito Miki, Hirotaka Terai, Thomas Gerrits, Masahide Sasaki

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


High-dimensional, frequency-entangled photonic quantum bits (qudits for d-dimension) are promising resources for quantum information processing in an optical fiber network and can also be used to improve channel capacity and security for quantum communication. However, up to now, it is still challenging to prepare high-dimensional frequency-entangled qudits in experiments, due to technical limitations. Here we propose and experimentally implement a novel method for a simple generation of frequency-entangled qudtswith d > 10 without the use of any spectral filters or cavities. The generated state is distributed over 15 kmin total length. This scheme combines the technique of spectral engineering of biphotons generated by spontaneous parametric down-conversion and the technique of spectrally resolved Hong-Ou-Mandel interference. Our frequency-entangled qudits will enable quantum cryptographic experiments with enhanced performances. This distribution of distinct entangled frequency modes may also be useful for improved metrology, quantum remote synchronization, as well as for fundamental test of stronger violation of local realism.

Original languageEnglish
Article number015004
JournalQuantum Science and Technology
Issue number1
Publication statusPublished - 2016 Aug 1
Externally publishedYes


  • Frequency-entangled qudits
  • Hong-Ou-Mandel interference
  • Spectral engineering of biphotons

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science (miscellaneous)
  • Physics and Astronomy (miscellaneous)
  • Electrical and Electronic Engineering


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