The flexible network design can simplify accurate comparisons of the latest atomic clocks operating at different frequencies and in different locations. The research also may have applications in remote sensing and secure communications.
Described in the May issue of Nature Photonics,* the prototype NIST network demonstrates the first remote synchronization of light waves from two "frequency combs"—advanced laboratory tools for precisely measuring frequencies of light. The two combs have fine "teeth" marking precise frequencies in different but overlapping bands. If light waves at identical frequencies are merged, they can either overlap exactly or be "out of phase" (that is, their oscillations are at the same frequency but start at different times). Light waves at different frequencies never overlap exactly but, with great effort, can be made to overlap out of phase in the same patterns in repeated experiments. The NIST network is designed to do exactly that, thus reducing channel "noise" that would result from mismatches. The stability of the lasers and low "jitter" of the synchronized waves means the original signal character is always preserved.
The network also showcases record performance in a frequency comb produced from an erbium fiber laser, an alternative to the original frequency comb generated from a titanium-sapphire crystal, also developed at NIST. Scientists recently reduced the noise in the fiber-based comb enough to improve its stability 30-fold, achieving performance comparable to the state-of-the-art Ti:Sapphire frequency comb used as the second comb in the new NIST network. Fiber-based frequency combs have the potential to be more compact and less expensive; they also measure the lower, near-infrared frequencies of light that are used in telecommunications.
The prototype network spans three-quarters of a kilometer and connects three different laboratories on the NIST Boulder, Colo., campus. The designers say it could be extended to 50 km or more without any loss in performance. To showcase the capability of the two frequency combs (which operate on different principles) to precisely compare vastly disparate optical frequencies across great distances, both combs are stabilized by the same source of 1126 nm laser light, so that each tooth of each comb is locked to a single frequency. In addition, laser light at 1535 nm laser, stabilized by one comb, is compared to 1535 nm light generated from the second comb, and the stability of the beat frequency (representing the difference between them) is analyzed to evaluate network performance.
Laura Ost | EurekAlert!
New technology enables 5-D imaging in live animals, humans
16.01.2017 | University of Southern California
Fraunhofer FIT announces CloudTeams collaborative software development platform – join it for free
10.01.2017 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction