Physics World May 19, 2020 Development of a dynamically tunable OAM light source is a critical step in the realization of OAM modulation and multiplexing. An international team of researchers (USA – University of Pennsylvania, Northeastern University, Italy, Spain) harnessed the properties of total momentum conservation, spin-orbit interaction, and optical non-Hermitian symmetry breaking, demonstrated an OAM-tunable vortex microlaser, providing chiral light states of variable topological charges at a single telecommunication wavelength. The scheme can be further scaled up for simultaneous multivortex emissions in a flexible manner. The work provides a route for the development of the next generation of multidimensional […]
Category Archives: Communications technology
Magnetoacoustic waves: Towards a new paradigm of on-chip communication
Phys.org April 6, 2020 An international team of researchers (Spain, Germany) designed an experiment to image and quantify the magnetization dynamics generated by SAW. The results clearly showed that magnetization waves exist at distinct frequencies and wavelengths and that it is possible to create wave interferences. The interference patterns of magnetization waves provide new avenues for manipulation of these waves at room temperature. As magnetization waves are coupled to the acoustic waves, they can travel long distances and have larger amplitudes than spin waves. As magnetoacoustic waves have more energy efficiency and larger spatial extension they are considered potential information […]
Extreme high-frequency signals enable terabits-per-second data links
Phys.com March 31, 2020 A team of researchers in the US (Brown University, industry) tested sending extremely high-frequency 200 GHz signals through a device with two wires running parallel inside a sheath with a large diameter that facilitates increased mixing of the waveguide modes. These mixtures enable the transmission of parallel noninterfering data channels. They demonstrated that the waveguide could support a data rate of 10 terabits per second. Their work demonstrates the feasibility of this approach to high-rate data transmission…read more.
Physicist from Hannover develops new photon source for tap-proof communication
EurekAlert March 27, 2020 Sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors an international team of researchers (UK, Japan, Germany) has demonstrated two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications much more secure in the future….read more. Open Access TECHNICAL ARTICLE
World record transmission of 172 Tb/s over 2040km distance coupled-3-core multi-core fiber
EurekAlert April 2, 2020 Using the product of data-rate and distance as a general index of transmission capacity, researchers in Japan achieved 351 petabit/s x km, more than doubling the current world record in standard outer diameter optical fibers employing space-division multiplexing. The coupled-core multi-core fiber requires signal processing on the receiving side after transmission, but the signal processing load is less compared to more commonly investigated few-mode fibers. The fiber has the same outer diameter as standard optical fibers which allows converting such a fiber into a cable with existing technologies and equipment, simplifying a timely adoption of coupled-core […]
Li-Fi Scrubs Into the Operating Room
IEEE Spectrum March 13, 2020 An international team of researchers (Germany, Czech Republic) set up multiple Li-Fi transmitters and receivers in a neurosurgery operating room in Prague. In a series of tests, the Li-Fi system managed to transfer data quickly and without complete signal loss. They achieved data rates of up to 600 megabits per second. Because Li-Fi uses higher-frequency light than Wi-Fi does, it could, in theory, have a higher bandwidth and therefore transmit data more quickly. Unlike Wi-Fi’s radio frequencies, which can pass through walls, optical light is easily blocked by humans or objects. To get around this […]
New Antenna Will Boost UAV Communication with Satellites
IEEE Spectrum March 10, 2020 Conventional sabre-like antennas generate a donut-shape radiation pattern, which provides an omnidirectional coverage and is ideal for air-to-ground communication. However, a donut-shape pattern has a null at its zenith which inhibits communication with other satellites. To provide signal directly above the antenna researchers in China designed a novel sabre-like antenna incorporated two metal radiators into the design. The first is a monopole, which is perpendicular to the ground with an omnidirectional pattern. The second is a dipole, which is parallel to the ground with broadside pattern – creating a signal that fills the blind spot […]
Team develops optical communications technology to double data transfer speed
Phys.org February 24, 2020 Researchers in South Korea have designed real-time pulse amplitude modulation-4 (PAM-4) digital signal processing including forward error correction for a C-band inter-datacenter network. The PAM-4 DSP is intended to compensate for chromatic dispersion and provide dispersion tolerance. A decision feedback equalizer and maximum likelihood sequence equalizer were employed for the dispersion compensation. A low-density parity check code was used to increase coding gain. They have empirically proved the feasibility of 25 km transmission without error-floor sign, corresponding to a dispersion compensation capacity of 425 ps/nm and confirmed 35 km ∼ 85 km error-free transmission for inter-datacenter […]
Using sound and light to generate ultra-fast data transfer
Science Daily February 11, 2020 To be able to send data at increased speeds, the lasers need to be modulated very rapidly: switching on and off or pulsing around 100 billion times every second. Instead of using external electronics, researchers in the UK used acoustic waves to vibrate the quantum wells inside the quantum cascade laser. The acoustic waves were generated by the impact of a pulse from another laser onto an aluminium film that caused the film to expand and contract, sending a mechanical wave through the quantum cascade laser. They were able to control the light output by […]
Building an Orbiting Internet Just for Satellites
IEEE Spectrum January 23, 2020 Small satellites in the low earth orbit depend on NASA’s Tracking and Data Relay Satellite System (TDRSS) to route signals from satellites to the correct ground stations when the satellite is on the other side of the earth. TDRSS is rarely accessible to companies, prohibitively expensive to use, and over 25 years old. To alleviate these problem a company in the US is creating a commercial replacement for TDRSS by building a constellation of many tiny satellites in LEO. The satellites will form the backbone of a space-based mesh network operating much like an Internet […]