Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Atomic clock signals may be best shared by fiber-optics

06.03.2007
Time and frequency information can be transferred between laboratories or to other users in several ways, often using the Global Positioning System (GPS).

But today's best atomic clocks are so accurate—neither gaining nor losing one second in as long as 400 million years—that more stable methods are needed. The best solution may be to use lasers to transfer data over fiber-optic cables, according to scientists at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.

The use of fiber-optic channels to transfer time signals allows accurate comparisons of distantly located atomic clocks of different types. This could lead, for example, to enhanced measurement accuracy in experiments to determine whether so-called "constants of nature" are in fact changing. Sharing of clock signals via fiber also will enable synchronization of components for advanced X-ray sources at linear accelerators, which may power studies of ultrafast phenomena in chemistry, biology, physics and materials science; or link arrays of geographically distributed radio telescopes to produce the power of a giant telescope.

Three state-of-the-art techniques for distributing ultra-stable time and frequency signals over fiber are described in a new review article* by NIST Fellow Jun Ye's group at JILA. Fibers can be far more stable, especially when efforts are made to cancel molecules along the transmission path, than the paths through free-space used by GPS, which requires days of measurement averaging to accurately compare today's best frequency standards. Moreover, considerable fiber-optic infrastructure already exists. For instance, the new paper is based largely on research performed on a 3.45-km fiber link installed in underground conduits and steam tunnels between JILA and NIST laboratories in Boulder.

Microwave frequency signals such as from NIST's standard atomic clock www.nist.gov/public_affairs/techbeat/tb2005_0923.htm#clock can be distributed over fiber using a continuous-wave (cw) laser. Another method can transfer more accurate optical frequency references such as NIST's mercury ion clock www.nist.gov/public_affairs/releases/mercury_atomic_clock.htm or JILA's strontium clock with a cw laser and disseminate signals to both optical and microwave users using an optical frequency comb www.nist.gov/public_affairs/newsfromnist_frequency_combs.htm. As a third option, microwave and optical frequency references can be transmitted simultaneously using a frequency comb.

Noting that gravitational effects may eventually limit ground-based atomic clocks, the paper suggests someday creating a network of optical atomic clocks in space, which might be used to make flawless distance measurements, transfer clock signals to different locations, and accurately map the Earth's gravity distribution.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Information Technology:

nachricht A novel hybrid UAV that may change the way people operate drones
28.03.2017 | Science China Press

nachricht Timing a space laser with a NASA-style stopwatch
28.03.2017 | NASA/Goddard Space Flight Center

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>