Phys.org November 28, 2018 For practical long-distance quantum communication room-temperature atomic vapours are important. Atomic motion has so far limited the single-excitation lifetime in such systems to the microsecond range. Researchers in Denmark have demonstrated that lifespan of the quantum state at room temperature can be extended to about a quarter of a millisecond. They used a small glass container, filled with Cesium atoms, in which they were able to load, store and retrieve single photons from, the quantum states necessary for the repeater. This technique improves the life span of the quantum states at room temperature a hundred times…read […]
Category Archives: Communications technology
New Spot-Beam Antennas Boost Communication Satellites’ Bandwidth
IEEE Spectrum September 28, 2018 A company based in the US has built massive communications satellites. The spot beams produced by antennas onboard focus in slightly different directions, allowing the same spectrum bands to be used multiple times without interference. Spot beams ultimately function similarly to cell towers. Eventually, the 18V and 19V will look down on Earth with their spot beams and wide beams. The 18V and 19V use the Ku (12 to 18 gigahertz) and Ka (26 to 40 GHz) bands for their spot beams and wide beams…read more.
Russian scientists have increased the Internet speed up to one and a half times
Eurekalert August 31, 2018 Researchers at the University of Missouri have developed an algorithm based on a special routing method which provides quick access to the most powerful large data processing centers in the world. The quality and speed of data transmission is achieved due to the superior constrained shortest path finder algorithm made by the scientists. Thus, the data transmission speed can be increased up to 50%. This is relevant for solving problems that require high-precision calculations both in the field of fundamental science and for the implementation of applied projects. According to the scientists, to use this algorithm, […]
Quantum dot floating gates improve light-erasable memories
Physics World August 3, 2018 Researchers in South Korea have significantly improved the performance of photoresponsive flash memories made from OFETs by making use of floating gates based on cadmium selenide quantum dots whose surfaces have been modified. They found that modifying the surfaces of the dots affected the performance of the memories and found that capping small ligands of octadecylphosphonic and fluorinated molecules improved the diffusion of holes between the dots and the conducting channels in the devices. The new devices have memory ratios of over 105 between OFF and ON bi-stable current states for over 10,000 seconds and […]
Light, finely sliced
Nanowerk July 16, 2018 Current technology for polarization beam splitters is limited to extinction ratio of around 25 decibels which is high enough to affect high-speed data transmission. Researchers in Singapore conceptualized design for a three-waveguide device and verified its feasibility on computer simulation. They confirmed its vastly improved extinction ratio of 40 decibel, representing a further 30-fold reduction in polarization crosstalk. The research is a breakthrough in improving high-performance data transmission systems, as well as applications in quantum computing… read more. TECHNICAL ARTICLE
A silicon-nanoparticle photonic waveguide
Nanowerk July 16, 2018 To efficiently transport light on small scales, researchers in Singapore have developed a more efficient method that involves a string of cylindrical silicon nanoparticles. The first nanoparticle is excited using light and then measured the light that reaches another nanoparticle further down the line. They found the fall in the light intensity to be low. The nanoparticles are not in direct contact with each other. Instead, light is transferred to the next particle through magnetic-field resonances. Although each particle is a resonant scatterer when they are lined up they work as a single waveguide without leaking […]
100 times faster broadband is coming: 5G passes first test
Science Daily July 6, 2018 With phase one of 5G global industry standards just being completed which focuses on 5G enhanced mobile broadband, research is now moving to address 5G technology to support ultra-reliable and ultra-low-latency connectivity for “vertical industries”. Researchers in the UK focus on the new frontiers of 5G, as well as investigating future deployment by operators, including indoor coverage and spectrum coexistence in newly assigned 5G frequencies in 3.5 Ghz and lower mm-wave bands. They have successfully completed the measurements of the indoor coverage of 5G signals. 5G is expected to be commercially available as early as […]
Fiber-optic transmission of 4,000 km made possible by ultra-low-noise optical amplifiers
Eurekalert July 5, 2018 The capacity and reach of long-haul fiber optical communication systems is limited by in-line amplifier noise and fiber nonlinearities. An international team of researchers (Sweden, Estonia) has demonstrated a multi-channel-compatible and modulation-format-independent long-haul transmission link with in-line phase-sensitive amplifiers with an improvement of 5.6 times at optimal launch powers with the phase-sensitively amplified link operating at a total accumulated nonlinear phase shift of 6.2 rad. The link transmits two data-carrying waves, thus occupying twice the bandwidth and propagating twice the total power compared to the phase-insensitively amplified link… read more. Open Access TECHNICAL ARTICLE
Multiple lasers could be replaced by a single microcomb
Science Daily June 12, 2018 An international team of researchers (Sweden USA – Purdue University) reports the first coherent-transmission experiments using 64-quadrature amplitude modulation encoded onto the frequency lines of a dark-pulse comb. The high conversion efficiency of the comb enables transmitted optical signal-to-noise ratios above 33 dB, while maintaining a laser pump power level compatible with state-of-the-art hybrid silicon lasers. The research helps to better understand the formation of dark pulses in microresonators and their potential use in optical communications. The research could lead to faster and more power-efficient optical communication links in the future… read more. Open Access TECHNICAL […]
Antiferromagnetic materials allow for processing at terahertz speeds
Science Daily May 24, 2018 An international team of researchers (Czech Republic, Germany, UK, Switzerland, USA – Texas A&M, Saudi Arabia) has demonstrated at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. The work opens the path toward the development of memory-logic technology reaching the terahertz band… read more. Open Access TECHNICAL ARTICLE 1 , TECHNICAL ARTICLE 2