Featured Research

from universities, journals, and other organizations

Atomic Clock Signals May Be Best Shared By Fiber-optics

Date:
March 4, 2007
Source:
National Institute of Standards and Technology
Summary:
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 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.

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.

Related Articles


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 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 or JILA's strontium clock with a cw laser and disseminate signals to both optical and microwave users using an optical frequency comb. 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.

This work was supported by the Office of Naval Research, National Aeronautics and Space Administration, NIST and the National Science Foundation.

* S.M. Foreman, K.W. Holman, D.D. Hudson, D.J. Jones, and J. Ye. Remote transfer of ultrastable frequency references via fiber networks. Invited Review, Review of Scientific Instruments. Vol. 78, No. 228. Published on-line Feb. 28, 2007.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology. Note: Materials may be edited for content and length.


Cite This Page:

National Institute of Standards and Technology. "Atomic Clock Signals May Be Best Shared By Fiber-optics." ScienceDaily. ScienceDaily, 4 March 2007. <www.sciencedaily.com/releases/2007/03/070302130946.htm>.
National Institute of Standards and Technology. (2007, March 4). Atomic Clock Signals May Be Best Shared By Fiber-optics. ScienceDaily. Retrieved January 26, 2015 from www.sciencedaily.com/releases/2007/03/070302130946.htm
National Institute of Standards and Technology. "Atomic Clock Signals May Be Best Shared By Fiber-optics." ScienceDaily. www.sciencedaily.com/releases/2007/03/070302130946.htm (accessed January 26, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, January 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Obama Reveals Nuclear Breakthrough on Landmark India Trip

Obama Reveals Nuclear Breakthrough on Landmark India Trip

Reuters - News Video Online (Jan. 25, 2015) In a glow of bonhomie, U.S. President Barack Obama and Indian Prime Minister Narendra Modi unveil a deal aimed at unlocking billions of dollars in nuclear trade. Pavithra George reports. Video provided by Reuters
Powered by NewsLook.com
NTSB: Missing Planes' Black Boxes Should Transmit Wirelessly

NTSB: Missing Planes' Black Boxes Should Transmit Wirelessly

Newsy (Jan. 23, 2015) In light of high-profile plane disappearances in the past year, the NTSB has called for changes to make finding missing aircraft easier. Video provided by Newsy
Powered by NewsLook.com
Iconic Metal Toy Meccano Goes Robotic

Iconic Metal Toy Meccano Goes Robotic

Reuters - Innovations Video Online (Jan. 22, 2015) Classic children&apos;s toy Meccano has gone digital, releasing a programmable kit robot that can be controlled by voice recognition. The toymakers say Meccanoid G15 KS is easy to use and is compatible with existing Meccano pieces. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
The VueXL From VX1 Immersive Smartphone Headset!

The VueXL From VX1 Immersive Smartphone Headset!

Rumble (Jan. 22, 2015) The VueXL from VX1 is a product that you install your smartphone in and with the magic of magnification lenses, enlarges your smartphones screen so that it&apos;s like looking at a big screen TV. Check it out! Video provided by Rumble
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