A5065516802- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Measurement and Metrology Techniques
- Spectroscopy and Laser Applications
- Quantum optics and atomic interactions
- Advanced Fiber Optic Sensors
- Laser Design and Applications
- Advanced Photonic Communication Systems
- Network Time Synchronization Technologies
- Atomic and Subatomic Physics Research
- Photonic and Optical Devices
- Optical Network Technologies
- Analytical Chemistry and Sensors
- Optical measurement and interference techniques
- Scientific Measurement and Uncertainty Evaluation
- Horticultural and Viticultural Research
- Advanced Measurement and Detection Methods
- Sensor Technology and Measurement Systems
- Geophysics and Sensor Technology
- Botanical Studies and Applications
- Railway Engineering and Dynamics
- Agriculture and Biological Studies
- Structural Health Monitoring Techniques
Czech Academy of Sciences, Institute of Scientific Instruments
2015-2025
CESNET, zájmové sdružení právnických osob
2021
Delft University of Technology
2016
Challenging experiments for tests in fundamental physics require highly coherent optical frequency references with suppressed phase noise from hundreds of kHz down to μHz Fourier frequencies. It can be achieved by remote synchronization many interconnected stabilized fibre links. Here we describe the path realize a delocalized reference spectroscopy isomeric state nucleus Thorium-229 atom. This is prerequisite realization next generation an clock - nuclear clock. We present established 235...
The contribution reviews actual trends in the design of molecular iodine reference cells intended for laser standards operated space-related applications and which were recently developed at ISI CAS. need optical setup compactness robustness introduced multipass arrangements, leading to reduced system weight volume while maintaining long beam–absorber interaction lengths. resilience harsh environmental conditions, especially during mission launch, reliability whole lifetime led investigation...
The infrastructure essentialities for accurate time and stable frequency distribution are presented. Our solution is based on sharing fibers a research educational network carrying live data traffic with transfer in parallel. Accurate transmission uses mainly dark channels amplified by dedicated bidirectional amplifiers the same propagation path both directions of transmission. This paper targets challenges related to transmission, particularly, directional nonreciprocities.
Fiber optic infrastructure is essential in the transmission of data all kinds, both for long haul and shorter distances cities. Optical fibers are also preferred infrastructures inside buildings, especially highly secured organizations government facilities. This paper focuses on a reference measurement analysis optical fiber cables sensitivity to acoustic waves. Measurement was carried out an anechoic chamber ensure stable conditions pressure range from 20 Hz kHz. The frequency response,...
Optical fiber links for distribution of highly-stable optical frequencies were experimentally tested by many metrology laboratories in the past fifteen years. But recent development new sensors industrial application puts demands on a technology transfer this high-end from laboratory experiments to real industry. The remote calibration interrogators Fiber Bragg Grating strain sensory networks is one important examples. We present 306 km long link established Czech Republic where coherent...
We present a preliminary study of bidirectional ultra-stable optical frequency and precise time transmission over 406 km long path in the telecom-grade fiber optic infrastructure dense wavelength division multiplexing. The main challenge this application is need amplification to compensate for signal loss. Directional non-reciprocities transfer are evaluated together with their uncertainties. Solutions proposed significantly limit final uncertainty.
In this work we present a design of an external optical cavity based on Fabry-Perot etalons applied to 100 MHz Er-doped fiber frequency comb working at 1560 nm increase its repetition frequency. A is constructed transportable cage system with two silver mirrors in plano-concave geometry including the mode-matching lenses, coupled collimation package and detection unit. The enables full 3D angle mirror tilting x-y off axis movement as well distance between mirrors. We demonstrate by direct...
The contribution reports on the current state of fibre link for phase-coherent transfer optical frequency between ISI CAS (Brno, CZ) and CESNET (Prague, CZ). 306 km long is operated an internet communication in a dedicated 1540–1546 nm DWDM window. narrow linewidth laser Kohereas ADJUSTIK working at 1540.5 locked to nearest tooth stabilized comb referenced by H-Maser serves as standard transmitting side.
Precise time and/or stable optical frequency transfers over fiber are more and deployed presently. Parallel transmission with telecommunication signals is often necessary, especially due to high intercity rental costs. This parallel traffic exhaust both low loss windows in single mode fibers (Conventional Long, together 1530-1610 nm) where mature Erbium Doped Fiber Amplifiers available. And very typically some additional spectral guard-bands required. In our contribution we present results...
In the article, we introduce Czech Infrastructure for Time and Frequency activity which is a non-commercial, open focused on transfer of accurate time very stable frequency using optical networks. The national infrastructure operated top CESNET network infrastructure, to have operational costs under control. We briefly summarize history its development, together with used types stabilization. also address running planned upgrades future development plans regarding wavelength bands considered...
Long distance precise frequency and accurate time transfer methods based on optical fiber links have evolved rapidly in recent years, demonstrating excellent performance. They are attractive both for very high-performance applications as a secure alternative complement to radio- satellite-based methods. In this paper, we present development of infrastructure such transmission containing 700+km lines, with planned cross border connectivity. According our knowledge, will be the third line...
The development of absolute distance measurement methods have been enabled by new kind lasers, special digital signal processing electronics, algorithms and materials for optics. phenomenon the mode-lock femtosecond pulse laser increased a number potential applications with surveying where that stable generator very short periodically repeated coherent pulses can be used. main aim work is description precise measuring method scale which able to determine length unknown direct traceability...
We report a measurement of optical fiber cables sensitivity to acoustic waves. An anechoic room was utilized for the measurement. Several objective parameters were evaluated w.r.t. various types cables.
Precise time and ultra-stable optical frequency transfers over fiber networks are deployed relatively often these days. When size of such infrastructure for precise bidirectional transmission is becoming significant, aspects associated with operational cost needed deployment must be considered. First can decreased via sharing telecommunication traffic, however spectral allocation considered carefully to avoid mutual disturbance versus data allow future accommodation growing demands. In text,...
Precise time and ultra-stable optical frequency transfers over fiber networks are deployed often in the present days. When size of such infrastructure for precise bidirectional transmission is becoming significant, aspects associated with operational costs needed deployment must be considered. First can decreased via sharing telecommunication traffic, however spectral allocation considered carefully to avoid mutual disturbance versus data, allow future accommodation growing demands. In text,...
There has been an increased focus on precise time and frequency transmission dissemination at a national international level recently. We would like to present the situation in Czech Republic, our strategy, approach, experience with non-commercial, cost-effective solution that utilizes shared optical networks. The presented provides accurate stable lower operational cost, utilizing spectrum of CESNET3 network infrastructure. are committed future developments upgrades will include next...
The laser spectroscopy is a fundamental approach for the realisation of traceable optical frequency standards. In 1:55 μm wavelength band, widely used in telecommunications, acetylene typical and most widespread absorption media. We present our investigation using hydrogen cyanide (HCN) as cost-efficient readily available alternative, that also provides wider span (from 1527nm to 1563 nm). have compared practical aspects new media comparison existing experience with an outlook carry out...
Methods for long-distance time and frequency transfer over optical fibers have demonstrated excellent performances are evolving rapidly. CLONETS is a European Union-funded coordination support action intended to facilitate the vision of sustainable, pan-European fiber network precise reference dissemination. © 2019 The Author(s)
Optical fibers are becoming commonly used beside data transmissions for dissemination of ultra-precise and stable quantities or alternatively as distributed sensors example acoustic mechanic vibrations, seismic waves, temperature etc. There have been developed methods these transfers their stabilization, allowing thus to achieve excellent performances. Such performance is bound with utilization single physical medium both ways propagation. These attractive very high-performance applications...
Dynamic development of long-distance methods time and frequency signals transmission over optical fibers is giving the opportunity to create network with dedicated clock services. In order prepare deployment this technology for a sustainable, pan-European fibre network, providing high-performance services European research infrastructures supporting wider industry society, CLONETS project, funded by Commission in H2020 program, coordination support action intended accelerate transfer these...
The paper reports on the transfer of stable optical frequency through free-space testbed and a fiber link testbed. measurement results show phase noise channel without turbulence, with atmospheric turbulence active stabilization received wave by MEMS mirror. are compared 1-Hz linewidth laser.
Long-distance time and frequency transfer methods based on optical fibre links have evolved rapidly in recent years, demonstrating excellent performance for considerable promise accurate transfer. CLONETS-DS is a European Union-funded research innovation action intended to facilitate the vision of sustainable, pan-European network precise reference dissemination.