Time and Frequency Activities at NICT, Japan

Transcription

1 Time and Frequency Activities at NICT, Japan Yasuhiro Koyama, Kuniyasu Imamura, Tsukasa Iwama, Shin'ichi Hama, Jun Amagai, Ryuichi Ichikawa, Yuko Hanado, and Mizuhiko Hosokawa National Institute of Information and Communications Technology 1

2 Organization of NICT NICT New Generation Network Research Center Network Architecture Group Photonic Network Group Advanced Device Research Group Space-Time Standards Group Quantum ICT Group New Generation Wireless Communications Research Center Information Security Research Center Applied Electromagnetic Research Center Kobe Advanced ICT Research Center Knowledge Creating Communication Research Center Universal Media Research Center

3 Four Research Projects Japan Standard Time Project Generation and maintenance of high quality Japan Standard Time (JST) and UTC (NICT) Dissemination of standard time by various methods (LF radio, NTP, dial-up,... etc.). Atomic Frequency Standards Project Develop and operate primary frequency standard and optical frequency standard systems. Satellite Time Management Projects Precise T&F transfer between ground and satellites (ETS-8 and Quasi-Zenith Satellite System). Space-Time Measurement Project R&D for precise T&F transfer and establishment of spatial reference frame by using TWSTFT, optical fiber transfer methods, and space geodetic techniques such as GPS and VLBI

4 Generation and Dissemination of Space, Time and Frequency Standards Space, Time and Frequency are the fundamental physical quantities in the field of Science and Technology. They are the important indexes of any kinds of digital information and are very important for safety and security of everybody s life. Developments of Next Generation Frequency Standards Emission of light from trapped Sr atoms. Trap Chamber New Frequency Standards in the Optical Region Precise Time and Frequency Transfer Methods and Space Geodesy ETS-8 (Engineering Test Satellite) QZSS (Quasi Zenith Satellite System) BIPM, National Timing Laboratories, Station A Station B + Ca Single Ion Trap Satellite T&F Transfer Precise T&F Transfer e-vlbi Towards better frequency standards International time and frequency transfer and satellite navigation Generation and Dissemination of Stable and Accurate Japan Standard Time (JST) Primary Frequency Standard LF Radio Dissemination of Frequency (10-12 ) and Time (10μs) Telephone Line JST System Internet (NTP Services) Atomic Clocks Determination and maintenance of UTC(NICT) to be consistent with UTC within 10nsec of difference and 5ns of variance. Frequency Calibration Services Time Business Services High Quality Frequency Calibration (5x10-14 ) Establish integrated space and time infrastructure to provide and certificate position and time. Integration of Space and Time Information Pedestrian navigation, certification of time and position of various information. Integrated Space and Time Infrastructure Provide accurate and reliable spatial and timing information to support secure and safe ICT. Protection of intellectual properties and electric commerce. Secure infrastructure for s, GIS, etc.

5 Time Keeping average 1 USNO (Washington DC) NICT (Tokyo) F (Paris) NTSC (Lintong) TL (Chung-Li) NIST (Boulder) SP (Boras) PL (Warszawa) PTB (Braunschweig) We optimized parameters for a frequency adjustment in May 2010, consequently the frequency stability of UTC(NICT) is improved in the middle term. 10 IT (Torino) Contribution Factors (%) for TAI Average of the Period Oct.2009-Sep.2010

6 Allan Deviation Short Term Stability Improvement of UTC(NICT) Optimization of Steering Parameters Evaluation Time : 5 days 10 days Convergence Period : 2 days 10 days Steering Interval : 24 hours 8 hours Before Optimization After Optimization

7 Frequency difference (10-15 ) Primary Frequency Standard Cesium atomic fountain primary frequency standard (NICT-CsF1) NICT-CsF1 has been in operation to realize the definition of the SI second since Last year, we did accuracy evaluation with NICT-CsF1 to contribute to the TAI three times. Ramsey fringe linewidth : 0.9Hz Frequency stability : 4 x /t 1/2 Current total frequency uncertainty : 1.3 x Ref: M. Kumagai et al, Metrologia 45 (2008) CsF1 SI second on geoid MJD

8 Allan Deviation Ion Trap Allan deviation of the 40 Ca + clock 1E nmLD+ULE Cavity Improved clock-transition spectrum by using a magnetic shield 1E-14 mj = 1/2> - mj = 1/2> components 1E nmLD+ULE +Ca + 1E-16 CSO+H Maser 1E+0 1E+1 1E+2 1E+3 1E+4 Averaging Time (s) Stability: (Frequency: (5) Hz) 60 Hz Frequency (Hz) Linewidth of ~60 Hz, the 5 th part of our previously observed linewidth

9 Allan standard deviation Optical Lattice Clock The spectroscopy for 87 Sr lattice clock transition was performed for lattice-loaded atoms, resulting in 45Hz (FWHM) spectral width. 45 Hz The clock laser frequency is locked to the atomic line. In other words, the operation as an atomic clock is achieved. Clock laser stability Sr vs H-maser H-maser ULE-stabilized clock laser The instability measurement against H-maser has resulted in just following the H-maser curve down to Averaging time (s)

10 Precise T&F Transfer T&F Transfer by Using Satellites T&F Transfer by VLBI (Very Long Baseline Interferometry) T&F Transfer by Using Optical Fiber

11 precision (random component) [ns] QZSS (Quasi Zenith Satellite System) 1st satellite was successfully launced on Sep The initial check-out is going on. Transportable TMS is under development; experiments in initial test thermal vacuum test (low) + final test thermal vacuum test (high) spec. 0.3ns@50dBHz for code phase 0.10 footprint of the orbit of QZSS (satellite 2 & 3 are not on the orbits yet) C/No [dbhz] Performance of the Time comparison unit for Ku-band two-way time transfer (by code phase) between QZSS satellite and the TMS to monitor the on-board atomic clocks (carrier phase measurements will also be performed) TMS: Time management station (at Tokyo and Okinawa)

12 T&F Transfer by TWSTFT and VLBI New TWSTFT system using Dual Pseudo Random Npoises (DPN) NICT has been conducting TWSTFT observations between NICT Koganei head quarter and Telecommunication Laboratories (TL, Taiwan) using new system since March 2010 with Intelsat-8 satellite link. GPS ETS-VIII TWSTFT VLBI VLBI1(multi channel band) VLBI2(wide band) VLBI = Very Long Baseline Interferometry GPS CP TW(DPN) ETS8(TCE) Time difference between Kashima and Koganei Results of NICT - TL TWSTFT (comparison with GPS results) Atomic Fountain Optical Clocks Kashima34-Kashima11 Geodetic Observation Calc/Solve 3C84 tracking data obs. delay a priori Frequency Stability The VLBI experiments achieves a frequency stability of the order of for more than 10 3 s averaging time.

13 Inter-comparison of Sr Lattice Clocks between U. Tokyo and NICT by Fiber Link f(sr, NICT) - f(sr, UT) (Hz) Sr lattice clock was fiber-linked to Prof. Katori s clock locating >50km apart in U. Tokyo Time (s) 09/20/2010 data456 > 50km Comparison better than is achieved in one second

14 Operations of TWSTFT links Asia Link = IS-8 Asia-Hawaii-US Link = GE23, AMC1 Asia-EU Link = IS-4 > AM-2

15 Dissemination Request /day (NTP) Ohtakadoya-yama Hagane-yama Frequency 40 khz 60 khz E.I.R.P 13 kw 23 kw Antenna 250 m height 200 m height Latitude 37 22' N 33 28' N Longitude ' E ' E JJY LF radio stations Request /month (tel-jjy)

16 Calibration Services 82 mm FPGA based GPS receiver unit for remote calibration Prototype small GPS receiver for remote calibration Refined LF radio signal receiver for remote calibration Optical fiber comb for optical frequency calibration

17 AP-RASC 10 / ATF2010 Date : Sep.22-26, 2010 Venue : Toyama, Japan Y. Koyama in Steering Committee M. Kajita in Program Committee P. Banerjee in Int. Advisory Board AP-RASC=Asia-Pacific Radio Science Conference (regional URSI meeting) 566 papers in total, 603 participants from 34 economies Following 5 sessions were recognized as ATF2010 joint sessions Calibration and dissemination in electromagnetic metrology Microwave frequency standards Optical frequency standards Optical frequency measurement Time and frequency transfer

18 Thank you very much for your attention.

19 Other Businesses (1) Special Issue on the MSI/MAPAN Journal of the Metrology Society of India (MAPAN) is planning to issue a special issue on Time and Frequency with an emphasis on optical frequency metrology. Guest Editors : Y. Koyama (NICT) and one additional person. Schedule Vol. 26, Issue No. 3, 2011 (Manuscripts by July 31, 2011) or Vol. 26, Issue No. 4, 2011 (Manuscripts by October 31, 2011) 6~7 papers review papers on Optical Lattice Clocks, Ion Trap Standards, Fiber Transfer, Optical Combs, Calibrations in the Optical Region, for examples. Suggestions or Ideas?

20 Other Businesses (2) Planning of Future Meetings URSI General Assembly and Scientific Symposium August 13-20, 2011, in Istanbul, Turkey Paper Submissions Due : February 11, 2011 Training Program in Time and Frequency Last Training was done at NICT, Japan, in October 2009 ATF2012 ATF2008 in Jakarta ATF2010 in Toyama, Japan in conjunction with AP-RASC'10