Electro-optic modulators for photonic quantum information processing

Hsin Pin Lo, Takuya Ikuta, Nobuyuki Matsuda, Toshimori Honjo, Hiroki Takesue

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Citations (Scopus)


We introduce our recent photonic quantum information processing experiments using the high-speed electro-optic modulator (EOM) based on a lithium niobate waveguides. First, we demonstrated the frequency shifter for single photons by using an optical single sideband (OSSB) modulator, which is based on the nested configuration of four phase modulators (PMs). By properly setting the RF modulation signal and the bias voltage to each PM, we can suppress unwanted sidebands to realize a frequency shifter that can tune the frequency of single photons with accuracy of an RF synthesizer. Using the OSSB modulator, we eliminated the frequency distinguishability between two single photons whose frequencies were different by 25 GHz, and as a result observed a Hong-Ou-Mandel interference with a visibility exceeding 90%. We also proposed and demonstrated a two-qubit controlled logic gate for time-bin qubits using a two-input, two-output optical switch. The switch enables us to individually perform different functions for two temporal bases as a time-dependent beam splitter, so that we can realize controlled-phase (C-Phase) gate for a time-bin qubit. We showed that the states of two separable single photons were entangled as a result of the C-Phase gate operation. We performed the quantum state tomography to obtain density matrices of the output states from the C-Phase gate for some specific input states, and confirmed that the averaged state fidelity to the pure states was 85%. These results indicate that the EOMs will be a useful tool for realizing advanced photonic quantum communication systems.

Original languageEnglish
Title of host publicationQuantum and Nonlinear Optics VI
EditorsQihuang Gong, Guang-Can Guo, Byoung Seung Ham
ISBN (Electronic)9781510631076
Publication statusPublished - 2019
EventQuantum and Nonlinear Optics VI 2019 - Hangzhou, China
Duration: 2019 Oct 212019 Oct 22

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceQuantum and Nonlinear Optics VI 2019


  • Electro-optical devices
  • Quantum Optics
  • Quantum information processing


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