Optical clocks can already be linked together physically through fiber-optic networks, but this approach still limits their usage in many electronic systems. “Because optical clocks have achieved unprecedented levels of accuracy and stability, linking the frequencies provided by these optical standards with distantly located devices would allow direct calibration of microwave clocks to the future optical SI second,” wrote Anne Curtis, a senior research scientist at the National Physical Laboratory in the United Kingdom, in an accompanying article. Today’s cesium-based atomic clocks require a month-long averaging process to achieve the same frequency stability that an optical clock can achieve in seconds. The improvement comes as many researchers expect the international standard that defines a second in time-the Système International (SI)-to switch over to optical clocks. Their highly precise method has an error of just one part in a quintillion (a one followed by 18 zeros). The new development and its implications for scientific research and engineering are described in the 22 May issue of the journal Science. “That has been the big piece that really made this new research work.”īy comparing two optical-to-electronic signal generators based on the output of two optical clocks, Quinlan and his colleagues created a 10-gigahertz microwave signal that synchronizes with the ticking of an optical clock. National Institute of Standards and Technology (NIST). “How do we preserve that timing from this optical to electronic interface?” says Franklyn Quinlan, a lead researcher in the optical frequency measurements group at the U.S. Such signals must be converted to microwave signals before electronic systems can readily make use of them. Those vibrations occur at microwave frequencies that can easily be used in electronic systems.īut newer optical atomic clocks, based on atoms such as ytterbium and strontium, vibrate much faster at higher frequencies and generate optical signals. Synchronizing modern electronic systems such as the Internet and GPS navigation is currently done using microwave atomic clocks that measure time based on the frequency of natural vibrations of cesium atoms. Now, researchers in the United States have figured out how to convert high-performance signals from optical clocks into a microwave signal that can more easily find practical use in modern electronic systems. They are far more accurate and stable than the current standard, which is based on microwave atomic clocks. Optical atomic clocks will likely redefine the international standard for measuring a second in time. Researchers converted the precise timekeeping of optical atomic clocks into microwave signals for electronics The entire set-up rests on a brass plate for mechanical stability. Wires connect the leads to the copper electrical circuit (top) used to extract microwave signals. The diode is surrounded by a gold-coated border in which electrical leads are embedded. ![]() Through the exploration of alternative physics architectures and novel component technologies, three sets of researchers have demonstrated early progress toward creating CSACs with 1000x improvement in temperature control, aging, and retrace.The black rectangle (center) is a high-speed semiconductor photodiode that converts laser pulses to superstable microwave frequencies. Calibration requirements and frequency drift can generate timing errors, making it difficult to achieve the highest degrees of accuracy and reliability in a portable package, the statement read. ![]() The CSACs offer unprecedented timing stability for their size, weight, and power (SWaP). Harnessing the power of atoms for precise timing requires a host of sophisticated and bulky technologies that are costly to develop and consume large amounts of energy,” DARPA said in a statement Tuesday. “Today’s communications, navigation, financial transaction, distributed cloud, and defense applications rely on the precision timing of atomic clocks – or clocks that track time based on the oscillation of atoms with the highest degrees of accuracy. Defense Advanced Research Projects Agency (DARPA) is presently working on an advanced version of its first-generation, battery-powered, miniature chip-scale atomic clock (CSAC) with 1000x performance improvements for positioning, navigation, and timing (PNT) applications.ĭARPA’s Atomic Clock with Enhanced Stability (ACES) program aims to build the next-generation atomic clock owing to the limitations of the now commercially available CSACs.
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