M. Amemiya

Publications (4)3.4 Total impact

• Conference Proceeding: Frequency measurement of a Sr optical lattice clock using a coherent optical link over a 120-km fiber

  F.-L. Hong, M. Musha, M. Takamoto, H. Inaba, S. Yanagimachi, A. Takamizawa, K. Watabe, T. Ikegami, M. Imae, Y. Fujii, M. Amemiya, K. Nakagawa, K. Ueda, H. Katori
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate a precision frequency measurement using a phase-stabilized 120-km optical fiber link over a physical distance of 50 km. The absolute frequency of the ⁸⁷Sr optical lattice clock is measured to be 429228004229874.1(2.4) Hz.
  Lasers and Electro-Optics, 2009 and 2009 Conference on Quantum electronics and Laser Science Conference. CLEO/QELS 2009. Conference on; 07/2009
• Source

  Available from: Ken'ichi Nakagawa

  Article: Measuring the frequency of a Sr optical lattice clock using a 120 km coherent optical transfer.

  F-L Hong, M Musha, M Takamoto, H Inaba, S Yanagimachi, A Takamizawa, K Watabe, T Ikegami, M Imae, Y Fujii, M Amemiya, K Nakagawa, K Ueda, H Katori
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate a precision frequency measurement using a phase-stabilized 120 km optical fiber link over a physical distance of 50 km. The transition frequency of the (87)Sr optical lattice clock at the University of Tokyo is measured to be 429228004229874.1(2.4) Hz referenced to international atomic time. The results demonstrate the excellent functions of the intercity optical fiber link and the great potential of optical lattice clocks for use in the redefinition of the second.
  Optics Letters 04/2009; 34(5):692-4. · 3.40 Impact Factor
• Source

  Available from: Ken'ichi Nakagawa

  Article: Measuring the frequency of a Sr optical lattice clock using a 120-km coherent optical transfer

  F.-L. Hong, M. Musha, M. Takamoto, H Inaba, S. Yanagimachi, A Takamizawa, K Watabe, T Ikegami, M. Imae, Y Fujii, M. Amemiya, K Nakagawa, K Ueda, H. Katori
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate a precision frequency measurement using a phase-stabilized 120-km optical fiber link over a physical distance of 50 km. The transition frequency of the 87Sr optical lattice clock at the University of Tokyo is measured to be 429228004229874.1(2.4) Hz referenced to international atomic time (TAI). The measured frequency agrees with results obtained in Boulder and Paris at a 6*10^-16 fractional level, which matches the current best evaluations of Cs primary frequency standards. The results demonstrate the excellent functions of the intercity optical fibre link, and the great potential of optical lattice clocks for use in the redefinition of the second. Comment: 14 pages, 3 figures
  11/2008;
• Source

  Available from: dtic.mil

  Article: Study of Frequency Transfer via Optical Fiber in the Microwave Domain

  M Amemiya, M Imae, Y Fujii, T Suzuyama, K Watabe, T Ikegami, H Tsuchida
  [show abstract] [hide abstract]
  ABSTRACT: Technical issues are investigated for a precise frequency transfer system using two-way signals by wavelength division multiplexing (WDM) in a single fiber. Bi-directional optical amplifiers are necessary to make the distance longer. Frequency stability is shown in the tandem optical amplifier link where the amplified spontaneous emission (ASE) noises are accumulated. Increasing transmission speed is effective for improving the system performance; however, chromatic dispersion of the fiber degrades the frequency stability significantly in an experiment with 10 GHz signal and 50-km fiber. The degradation can be improved by using 1550 nm zero-dispersion-shifted fiber (DSF) instead of SMF. Effects of polarization mode dispersion (PMD) and polarization scrambling are experimentally shown with a differential group delay (DGD) generator. It is also important to use stable oscillators for stability evaluation, since the time difference between the original and the received signal at the far end degrades the performance if the phase noise of the OSC source is not small enough.