Using graphene, researchers increase optical data transmission speed by a factor of at least 10,000.

Nanowerk  January 19, 2021 Conventional optical-fiber-based pulsed lasers have limits to increasing the number of pulses per second above the MHz level. Researchers in South Korea inserted an additional resonator containing graphene into a fiber-optic pulsed-laser oscillator that operates in the domain of femtoseconds (10-15 seconds). This increased data transmission and processing speeds significantly. They synthesized graphene, which has the characteristics of absorbing and eliminating weak light and amplifying the intensity by passing only strong light into the resonator. This allows the laser intensity change to be accurately controlled at a high rate, and thus the repetition rate of pulses […]

Perfect transmission through barrier using sound

Science Daily  December 23, 2020 Tunneling plays an essential role in many branches of physics and has found important applications. It is theoretically proposed that Klein tunneling occurs when, under normal incidence, quasiparticles exhibit unimpeded penetration through potential barriers independent of their height and width. A team of researchers in the US (UC Berkeley, Georgia Institute of Technology, Lawrence Berkeley National Laboratory) created a phononic heterojunction by sandwiching two types of artificial phononic crystals with different Dirac point energies. They demonstrated direct observation of Klein tunneling as shown by the key feature of unity transmission. Their experiment reveals that Klein […]

World’s First Successful Transmission of 1 Petabit per Second Using a Single-core Multimode Optical Fiber

NICT Japan  December 18, 2020 Researchers in Japan have demonstrated the possibility of combining highly spectral efficient wideband optical transmission with an optical fiber guiding 15 fiber modes that had a cladding diameter in agreement with the current industry standard of 0.125 mm. This was enabled by mode multiplexers and an optical fiber that supported wideband transmission of more than 80 nm over 23 km. The study highlights the large potential of single-core multi-mode fibers for high-capacity transmission using fiber manufacturing processes like those used in the production of standard multi-mode fibers. The results of this study were accepted for […]

Ultrathin spray-applied MXene antennas are ready for 5G

Science Daily  November 30, 2020 Only conventional metals meet the requirements for emerging RF devices so far. A team of researchers in the US (Drexel University, Villanova University, industry) has developed Ti3C2Tx MXene microstrip transmission lines with low‐energy attenuation and patch antennas with high‐power radiation at frequencies from 5.6 to 16.4 GHz. The antenna was manufactured by spray‐coating from aqueous solution. They demonstrated that an MXene patch antenna array with integrated feeding circuits on a conformal surface has comparable performance with that of a copper antenna array at 28 GHz, which is a target frequency in practical 5G applications. The […]

New fiber optic sensors transmit data up to 100 times faster

EurekAlert  November 16, 2020 Distributed optical fibre sensors deliver a map of a physical quantity along an optical fibre, providing a unique solution for health monitoring of targeted structures. An international team of researchers (China, Switzerland, Chile) propose a technique encoding the interrogating light signal by a single-sequence aperiodic code and spatially resolving the fibre information through a fast-post-processing. The code sequence is once forever computed by a specifically developed genetic algorithm, enabling a performance enhancement using an unmodified conventional configuration for the sensor. They demonstrated in Brillouin and Raman based sensors, both outperforming the state-of-the-art sensors. The new technique […]

Ultra-fast polymer modulators that can take the heat

Science Daily  November 13, 2020 Researchers in Japan took advantage of the high electro-optic activities, low dielectric constant, low propagation loss and ultra-high glass transition temperature of the developed side-chain electro-optic polymers to fabricate silicon-polymer hybrid modulator. It supports ultra-fast single-lane data rates up to 200 gigabits per second, excellent reliability, and exceptional signal fidelity at extremely high ambient temperatures up to 110 °C even after long-term exposure to high temperatures. It could provide ultra-fast and reliable interconnects for datacenters, 5G/B5G, autonomous driving, and aviation systems, effectively addressing the energy consumption issue for the next-generation optical communication…read more. Open Access TECHNICAL […]

Physicists develop efficient modem for a future quantum internet

Phys.org  November 5, 2020 A central research object is the interface between local quantum devices and light quanta that enable the remote transmission of highly sensitive quantum information. Researchers in Germany integrated a thin crystal of erbium-doped yttrium orthosilicate a cryogenic Fabry-Perot resonator leading to 56-fold enhancement of the emission rate with an out-coupling efficiency of 46%. They demonstrated that the emitter properties are not degraded. They observed ensemble-averaged optical coherence up to 0.54 ms, which exceeds the 0.19 ms lifetime of dopants at the cavity field maximum. The approach is also applicable to other solid-state quantum emitters, such as […]

Generating photons for communication in a quantum computing system

Phys.org  October 10, 2020 Realizing a fully connected network of quantum processors requires the ability to distribute quantum entanglement. For distant processing nodes, this can be achieved by generating, routing, and capturing spatially entangled itinerant photons. Researchers at MIT and MIT Lincoln Laboratory have demonstrated the deterministic generation of such photons using superconducting transmon qubits that are directly coupled to a waveguide. They generated two-photon N00N states and showed that the state and spatial entanglement of the emitted photons are tunable via the qubit frequencies. Using quadrature amplitude detection, they reconstructed the moments and correlations of the photonic modes and […]

5G wireless may lead to inaccurate weather forecasts

Rutgers University  September 24, 2020 The signals from the 5G frequency bands potentially could leak into the band used by weather sensors on satellites that measure the amount of water vapor in the atmosphere and affect weather forecasting and predictions. Researchers at Rutgers University used computer modeling to examine the impact of 5G “leakage” on forecasting the deadly 2008 Super Tuesday Tornado Outbreak in the South and Midwest. Based on modeling, 5G leakage power of -15 to -20 decibel Watts affected the accuracy of forecasting of precipitation (by up to 0.9 millimeters) during the tornado outbreak and temperatures near ground […]

Breakthrough Could Lead to Amplifiers for 6G Signals

IEEE Spectrum  September 24, 2020 Researchers at UC Santa Barbara have been developing a device that could be critical to efficiently pushing 6G’s terahertz-frequency signals out of the antennas of future smartphones and other connected devices. They show that N-polar GaN deep recess HEMTs grown on sapphire match the power performance of a device on SiC up to 14 V with 5.1 W/mm of output power density. At 16 V the device on sapphire starts to suffer from thermal effects but still demonstrated 5.5 W/mm with an associated 20.6% power-added efficiency. This work also examines the impact of encapsulating the […]