Featured Research

from universities, journals, and other organizations

Redefining time: Extremely precise clock signals transmitted over long distances

Date:
April 30, 2012
Source:
Optical Society of America
Summary:
Scientists have successfully sent a highly accurate clock signal across the many hundreds of kilometers of countryside that separate two institutions.

This is a map of Germany showing the path of the 920-kilometer-long optical fiber link from Max Planck Institute of Quantum Optics to the Federal Institute of Physical and Technical Affairs. The red houses represent amplifier stations.
Credit: Stefan Droste, Max Planck Institute of Quantum Optics

Atomic clocks based on the oscillations of a cesium atom keep amazingly steady time and also define the precise length of a second. But cesium clocks are no longer the most accurate. That title has been transferred to an optical clock housed at the U.S. National Institute of Standards and Technology (NIST) in Boulder, Colo. that can keep time to within 1 second in 3.7 billion years. Before this newfound precision can redefine the second, or lead to new applications like ultra-precise navigation, the system used to communicate time around the globe will need an upgrade.

Recently scientists from the Max Planck Institute of Quantum Optics, in the south of Germany, and the Federal Institute of Physical and Technical Affairs in the north have taken a first step along that path, successfully sending a highly accurate clock signal across the many hundreds of kilometers of countryside that separate their two institutions.

The researchers will present their finding at Conference on Lasers and Electro Optics (CLEO: 2012), taking place May 6 -11 in San Jose, Calif.

"Over the last decade a new kind of frequency standard has been developed that is based on optical transitions, the so-called optical clock," says Stefan Droste, a researcher at the Max Planck Institute of Quantum Optics. The NIST optical clock, for example, is more than one hundred times more accurate than the cesium clock that serves as the United States' primary time standard.

Extremely precise time keeping -- and the ability to communicate the world time standard across long distances -- is vital to myriad applications, including in navigation, international commerce, seismology, and fundamental quantum physics. Unfortunately, the satellite-based links currently used to communicate that standard are not up to the task of transmitting such a stable signal, so the second retains its less precise measure. Optical fiber links could work better, but had previously been tested only over short distances, such as those separating buildings on the same campus or within the same urban area.

"The average distance between institutes that operate frequency standards in Europe is on the order of a few thousand kilometers," notes Droste. "Spanning these great distances with an optical link is challenging not only because of the additional degradation of the transferred signal, but also because multiple signal conditioning stations need to be installed and operated continuously along the link path." Droste and his colleagues were able to overcome the challenges by installing nine signal amplifiers along a 920-kilometer-long fiber link. They successfully transferred a frequency signal with more than 10 times the accuracy than would be required for today's most precise optical clocks.


Story Source:

The above story is based on materials provided by Optical Society of America. Note: Materials may be edited for content and length.


Cite This Page:

Optical Society of America. "Redefining time: Extremely precise clock signals transmitted over long distances." ScienceDaily. ScienceDaily, 30 April 2012. <www.sciencedaily.com/releases/2012/04/120430105454.htm>.
Optical Society of America. (2012, April 30). Redefining time: Extremely precise clock signals transmitted over long distances. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/04/120430105454.htm
Optical Society of America. "Redefining time: Extremely precise clock signals transmitted over long distances." ScienceDaily. www.sciencedaily.com/releases/2012/04/120430105454.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins