Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331413
C. Calosso, E. Bertacco, D. Calonico, C. Clivati, G. Costanzo, M. Frittelli, F. Levi, S. Micalizio, A. Mura, A. Godone
It is well known that temperature variations and acoustic noise affect ultrastable frequency dissemination along optical fiber. Active stabilization techniques are in general adopted to compensate for the fiber-induced phase noise. However, despite this compensation, the ultimate link performances remain limited by the so called delay-unsuppressed fiber noise that is related to the propagation delay of the light in the fiber. In this paper, we demonstrate a data post-processing approach which enables us to overcome this limit. We implement a subtraction algorithm between the optical signal delivered at the remote link end and the round-trip signal. In this way, a 6dB improvement beyond the fundamental limit imposed by delay-unsuppressed noise is obtained. This result enhances the resolution of possible comparisons between remote optical clocks by a factor of 2. We confirm the theoretical prediction with experimental data obtained on a 47km metropolitan fiber link, and propose how to extend this method for frequency dissemination purposes as well.
{"title":"Novel techniques for optical fiber links beyond current practice","authors":"C. Calosso, E. Bertacco, D. Calonico, C. Clivati, G. Costanzo, M. Frittelli, F. Levi, S. Micalizio, A. Mura, A. Godone","doi":"10.1109/EFTF.2014.7331413","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331413","url":null,"abstract":"It is well known that temperature variations and acoustic noise affect ultrastable frequency dissemination along optical fiber. Active stabilization techniques are in general adopted to compensate for the fiber-induced phase noise. However, despite this compensation, the ultimate link performances remain limited by the so called delay-unsuppressed fiber noise that is related to the propagation delay of the light in the fiber. In this paper, we demonstrate a data post-processing approach which enables us to overcome this limit. We implement a subtraction algorithm between the optical signal delivered at the remote link end and the round-trip signal. In this way, a 6dB improvement beyond the fundamental limit imposed by delay-unsuppressed noise is obtained. This result enhances the resolution of possible comparisons between remote optical clocks by a factor of 2. We confirm the theoretical prediction with experimental data obtained on a 47km metropolitan fiber link, and propose how to extend this method for frequency dissemination purposes as well.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121038939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331485
Haixia Wang, T. Baron, G. Martin, W. Daniau, M. Pijolat, J. Brice, E. Courjon, S. Ballandras
This work is devoted to the reduction of temperature coefficient of frequency (TCF) of leaky-surface-acoustic-wave (LSAW) on (YXl)/42° Lithium Tantalate. Compound single crystal substrates based on LiTaO3 wafers bonded onto Silicon and thinned down to some tens μm are manufactured in that way. The leading idea consists in impeding the natural Tantalate thermal expansion using Silicon limited expansion. 2 GHz resonators have been built on these compound wafers to demonstrate the principle. Temperature-controlled tip-probing tests show on-trench absolute TCF smaller than 7 pmm.K-1. A representative set of resonator has been packaged and tested in a climatic chamber, yielding evidence of TCF much smaller than the one of the single-crystal substrate and even temperature compensation. Perspective and further developments of this work are discussed as a conclusion.
{"title":"Leaky SAW with reduced TCF on LT42/Silicon substrates","authors":"Haixia Wang, T. Baron, G. Martin, W. Daniau, M. Pijolat, J. Brice, E. Courjon, S. Ballandras","doi":"10.1109/EFTF.2014.7331485","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331485","url":null,"abstract":"This work is devoted to the reduction of temperature coefficient of frequency (TCF) of leaky-surface-acoustic-wave (LSAW) on (YXl)/42° Lithium Tantalate. Compound single crystal substrates based on LiTaO3 wafers bonded onto Silicon and thinned down to some tens μm are manufactured in that way. The leading idea consists in impeding the natural Tantalate thermal expansion using Silicon limited expansion. 2 GHz resonators have been built on these compound wafers to demonstrate the principle. Temperature-controlled tip-probing tests show on-trench absolute TCF smaller than 7 pmm.K-1. A representative set of resonator has been packaged and tested in a climatic chamber, yielding evidence of TCF much smaller than the one of the single-crystal substrate and even temperature compensation. Perspective and further developments of this work are discussed as a conclusion.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115367089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331564
S. Podogova, K. Mishagin
Experimental results of performance of frequency combining system for atomic clock ensemble are presented. Estimated frequency stability of averaged signal at the output of the system is improved in comparison to frequency stability characteristics of reference atomic clocks. Simple multi-scale frequency control algorithm for combining atomic clocks of different types is described. The idea of multi-scale frequency control is used for producing ensemble time scale algorithm.
{"title":"Frequency combining system for atomic clock ensembles","authors":"S. Podogova, K. Mishagin","doi":"10.1109/EFTF.2014.7331564","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331564","url":null,"abstract":"Experimental results of performance of frequency combining system for atomic clock ensemble are presented. Estimated frequency stability of averaged signal at the output of the system is improved in comparison to frequency stability characteristics of reference atomic clocks. Simple multi-scale frequency control algorithm for combining atomic clocks of different types is described. The idea of multi-scale frequency control is used for producing ensemble time scale algorithm.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126672996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331545
G. Bideberg, S. Ebenhag, K. Jaldehag, P. Hedekvist
Swedish standard time is regulated by law to follow UTC as maintained by the BIPM. The atomic clocks that are used to implement UTC(SP), the realization of UTC in Sweden, are located at four different sites and are reported to TAI using data from TWSTFT and GNSS links. The activities in the Time and Frequency laboratory at SP are presently undergoing an expansion with the construction of a new additional secure site and the implementation of a distributed time scale.
{"title":"Construction of a secure clock location for alternative realization of UTC(SP)","authors":"G. Bideberg, S. Ebenhag, K. Jaldehag, P. Hedekvist","doi":"10.1109/EFTF.2014.7331545","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331545","url":null,"abstract":"Swedish standard time is regulated by law to follow UTC as maintained by the BIPM. The atomic clocks that are used to implement UTC(SP), the realization of UTC in Sweden, are located at four different sites and are reported to TAI using data from TWSTFT and GNSS links. The activities in the Time and Frequency laboratory at SP are presently undergoing an expansion with the construction of a new additional secure site and the implementation of a distributed time scale.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121750783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331507
A. Czubla, R. Osmyk, P. Szterk, P. Krehlik, L. Sliwczynski, R. Szplet, Z. Jachna, K. Rozyc
In this paper, there are presented the last results of tests of TICs characteristics for precise time transfer links, especially for optical fiber links, performed at GUM in cooperation with AGH and WAT. Tests of TICs were done by application of a special dual channel 1/100 pps generator and a very simply method of comparison of the changes of phase frequency measurement with the changes of time interval measurements between 1 pps signals derived from the standard frequency signals. The obtained results show the existence of non-linearities in operation of time interval converters/ algorithms inside TICs and instabilities at time interval measurements, observed also when the measured time interval is kept constant. These results can be treated as a reference for further analysis of accuracy and precision of time transfer links based on TIC measurements as well as for further investigations of TICs characteristics.
{"title":"Verification of TIC characteristics for precise optical fiber time transfer links","authors":"A. Czubla, R. Osmyk, P. Szterk, P. Krehlik, L. Sliwczynski, R. Szplet, Z. Jachna, K. Rozyc","doi":"10.1109/EFTF.2014.7331507","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331507","url":null,"abstract":"In this paper, there are presented the last results of tests of TICs characteristics for precise time transfer links, especially for optical fiber links, performed at GUM in cooperation with AGH and WAT. Tests of TICs were done by application of a special dual channel 1/100 pps generator and a very simply method of comparison of the changes of phase frequency measurement with the changes of time interval measurements between 1 pps signals derived from the standard frequency signals. The obtained results show the existence of non-linearities in operation of time interval converters/ algorithms inside TICs and instabilities at time interval measurements, observed also when the measured time interval is kept constant. These results can be treated as a reference for further analysis of accuracy and precision of time transfer links based on TIC measurements as well as for further investigations of TICs characteristics.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123014131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331445
Wei Li, Yongliang Xu, Wei Guang
Time service of GNSS is the capability to make user to obtain UTC. A testing and evaluation method of GNSS time service performance is put forward in this paper. Using the UTC (NTSC) as the user's local time, through the GPS and Beidou multimode receiver signal, the time difference of UTC (NTSC) and UTC(k) broadcasted by GNSS is got, to amend the UTC (k) to UTC with the Circular T issued by BIPM, the complete time service is obtained. In order to evaluate the time service performance, the time difference of UTC(NTSC) and UTC is obtained with Circular T as a reference to be compared and analyzed with the time service results of GPS and Beidou. The results showed that the GPS traceability is slightly better than BDS. BDS is in the construction stage now, its traceability will improve with the further development of system.
{"title":"The time service performance evaluation of GNSS","authors":"Wei Li, Yongliang Xu, Wei Guang","doi":"10.1109/EFTF.2014.7331445","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331445","url":null,"abstract":"Time service of GNSS is the capability to make user to obtain UTC. A testing and evaluation method of GNSS time service performance is put forward in this paper. Using the UTC (NTSC) as the user's local time, through the GPS and Beidou multimode receiver signal, the time difference of UTC (NTSC) and UTC(k) broadcasted by GNSS is got, to amend the UTC (k) to UTC with the Circular T issued by BIPM, the complete time service is obtained. In order to evaluate the time service performance, the time difference of UTC(NTSC) and UTC is obtained with Circular T as a reference to be compared and analyzed with the time service results of GPS and Beidou. The results showed that the GPS traceability is slightly better than BDS. BDS is in the construction stage now, its traceability will improve with the further development of system.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124830177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331480
P. Krehlik, L. Sliwczynski
In this paper we present the idea of fiber optic time and frequency distribution system with tapping nodes along the link. We describe a principle of delay stabilization in tapping nodes and a procedure for calibration of time signal delay. Initial experimental results show TDEV below 1 ps for averaging time approaching 105 s, and calibration error below 25 ps in various lengths of fiber sections.
{"title":"Tapping nodes in actively stabilized fiber optic time transfer","authors":"P. Krehlik, L. Sliwczynski","doi":"10.1109/EFTF.2014.7331480","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331480","url":null,"abstract":"In this paper we present the idea of fiber optic time and frequency distribution system with tapping nodes along the link. We describe a principle of delay stabilization in tapping nodes and a procedure for calibration of time signal delay. Initial experimental results show TDEV below 1 ps for averaging time approaching 105 s, and calibration error below 25 ps in various lengths of fiber sections.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124891388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331492
M. DeMiguel-Ramos, T. Mirea, J. Olivares, M. Clement, J. Sangrador, E. Iborra, M. Barba
High frequency electroacoustic biosensors require the use of microfluidic systems to confine the liquid under test on the sensor surface. Owing to frequent conductive character of biochemical solutions, the contacting pads must be isolated from the active areas of the sensors by means of electrical extensions. At working frequencies in the GHz range, the parasitic effects of such extensions can worsen the overall electrical response of the resonators by dramatically reducing the quality factor at the resonant frequency. In this paper, we study the effects of electrical extensions in AlN-based solidly mounted resonators operating in the shear mode at 1.3 GHz. The design of these extensions as a stretch of coplanar waveguide allows us minimizing the parasitic effects and matching the impedance between the resonator and the external circuitry for excitation and readout. We present solutions to lead the contact pads 2 mm away from the active area without distortion of the resonator response. Resonators with electrical extensions of 1.5 mm and quality factors of more than 150 are obtained.
{"title":"Influence of the electrical extensions in AlN-BAW resonators for in-liquid biosensors","authors":"M. DeMiguel-Ramos, T. Mirea, J. Olivares, M. Clement, J. Sangrador, E. Iborra, M. Barba","doi":"10.1109/EFTF.2014.7331492","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331492","url":null,"abstract":"High frequency electroacoustic biosensors require the use of microfluidic systems to confine the liquid under test on the sensor surface. Owing to frequent conductive character of biochemical solutions, the contacting pads must be isolated from the active areas of the sensors by means of electrical extensions. At working frequencies in the GHz range, the parasitic effects of such extensions can worsen the overall electrical response of the resonators by dramatically reducing the quality factor at the resonant frequency. In this paper, we study the effects of electrical extensions in AlN-based solidly mounted resonators operating in the shear mode at 1.3 GHz. The design of these extensions as a stretch of coplanar waveguide allows us minimizing the parasitic effects and matching the impedance between the resonator and the external circuitry for excitation and readout. We present solutions to lead the contact pads 2 mm away from the active area without distortion of the resonator response. Resonators with electrical extensions of 1.5 mm and quality factors of more than 150 are obtained.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129011078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331502
J. Tratnik, Uros Dragonja, B. Batagelj
An electro-optical system for a multi-purpose user signal distribution with a temperature-drift compensation of a fiber link is presented. The delay drift is measured by a radio frequency RF phase comparison. A (coarse) wavelength division multiplexing (C)WDM technology is used for combining compensation and user signals. Temperature and other delay variations (e. g. vibrations) are compensated by an internal heated/cooled fiber spool and/or piezo-controlled fiber stretcher. A delay stability better than 1 ps peak-peak in a 16 hour period has been measured using a dedicated measurement setup. The system uses standard commercially available telecommunication optical components.
{"title":"Multi-purpose constant-delay optical link","authors":"J. Tratnik, Uros Dragonja, B. Batagelj","doi":"10.1109/EFTF.2014.7331502","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331502","url":null,"abstract":"An electro-optical system for a multi-purpose user signal distribution with a temperature-drift compensation of a fiber link is presented. The delay drift is measured by a radio frequency RF phase comparison. A (coarse) wavelength division multiplexing (C)WDM technology is used for combining compensation and user signals. Temperature and other delay variations (e. g. vibrations) are compensated by an internal heated/cooled fiber spool and/or piezo-controlled fiber stretcher. A delay stability better than 1 ps peak-peak in a 16 hour period has been measured using a dedicated measurement setup. The system uses standard commercially available telecommunication optical components.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130256626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-23DOI: 10.1109/EFTF.2014.7331436
T. Krawinkel, S. Schon, A. Bauch
Kinematic GNSS (Global Navigation Satellite System) single point positioning (SPP) requires epoch-wise estimation of a receiver synchronization error w.r.t. GNSS system time. Modeling this error source improves the accuracy of the up-coordinate and makes the adjustment more robust. In this paper, we discuss the performance of three different atomic frequency standards that were characterized in terms of their frequency stabilities at Physikalisch-Technische Bundesanstalt, Germany. We found significant differences to the manufacturer's data in terms of Allan deviations. In order to analyze the clock performance when connected to GNSS receivers, a static experiment was carried out at Leibniz Universität Hannover. Application of receiver clock modeling in kinematic SPP improves the RMS error of the up-coordinates up to 26% compared to epoch-wise receiver clock error estimation.
{"title":"Application of miniaturized atomic clocks in kinematic GNSS single point positioning","authors":"T. Krawinkel, S. Schon, A. Bauch","doi":"10.1109/EFTF.2014.7331436","DOIUrl":"https://doi.org/10.1109/EFTF.2014.7331436","url":null,"abstract":"Kinematic GNSS (Global Navigation Satellite System) single point positioning (SPP) requires epoch-wise estimation of a receiver synchronization error w.r.t. GNSS system time. Modeling this error source improves the accuracy of the up-coordinate and makes the adjustment more robust. In this paper, we discuss the performance of three different atomic frequency standards that were characterized in terms of their frequency stabilities at Physikalisch-Technische Bundesanstalt, Germany. We found significant differences to the manufacturer's data in terms of Allan deviations. In order to analyze the clock performance when connected to GNSS receivers, a static experiment was carried out at Leibniz Universität Hannover. Application of receiver clock modeling in kinematic SPP improves the RMS error of the up-coordinates up to 26% compared to epoch-wise receiver clock error estimation.","PeriodicalId":129873,"journal":{"name":"2014 European Frequency and Time Forum (EFTF)","volume":"14 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130550708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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