Low-loss, chip-scale programmable silicon photonic processor

Phys.org  November 7, 2022 Silicon photonics has unique advantages of ultra-high integration density as well as CMOS compatibility, and thus makes it possible to develop large-scale programmable optical signal processors. However, the high silicon waveguides propagation losses and the high calibration complexity for all tuning elements due to the random phase errors is a challenge. An international team of researchers (China, USA – Industry) demonstrated a programmable silicon photonic processor by introducing low-loss multimode photonic waveguide spirals and low-random-phase-error Mach-Zehnder switches. The waveguide spirals were designed to be as wide as 2 µm, enabling an ultralow propagation loss of 0.28 […]

Photon-controlled diode: An optoelectronic device with a new signal processing behavior

Phys.org  July 1, 2022 The photodetector is a key component in optoelectronic integrated circuits. Although there are various device structures and mechanisms, the output current changes either from rectified to fully-on or from fully-off to fully-on after illumination. According to researchers in China the device that changes the output current from fully-off to rectified should be possible. They designed a photon-controlled diode based on a n/n− molybdenum disulfide junction. Schottky junctions formed at the cathode and anode either prevent or allow the device to be rectifying, so that the output current of the device changes from fully-off to rectified. By […]

A new amplifying technique for weak and noisy optical signals

Phys.org  February 2, 2022 Mitigating the stochastic noise introduced during the generation, transmission, and detection of temporal optical waveforms remains a significant challenge across many applications. An international team of researchers (Canada, Spain) proposed a versatile concept for simultaneous amplification and noise mitigation of temporal waveforms, and successfully demonstrated on optical signals with bandwidths spanning several orders of magnitude, from the kHz to GHz scale. The concept was based on lossless temporal sampling of the incoming coherent waveform through Talbot processing. By reaching high gain factors (>100), they showed the recovery of ultra-weak optical signals, with power levels below the […]

Ultra-strong squeezing of light demonstrated for ultrafast optical signal processing

Phys.org  July 6, 2021 An international team of researchers (Singapore, USA – MIT) succeeded in squeezing light in time by a factor of 11. They demonstrated 3.0× spectral compression of 480 fs pulses while preserving the pulse energy. The strong compression achieved at low powers harnesses advanced on-chip device design, and the strong nonlinear properties of backend-CMOS compatible ultra-silicon-rich nitride, which possesses absence of two-photon absorption and 500× larger nonlinear parameter than in stoichiometric silicon nitride waveguides. By balancing the contributions from the dispersive and nonlinear stages, they could generate strong compression in either time or frequency. The work introduces an […]

Scientists tame photon-magnon interaction

Nanowerk  January 14, 2021 Microwave photon-magnon interaction has emerged in recent years as a promising platform for both classical and quantum information processing. Yet, this interaction had proved impossible to manipulate in real time. By smart engineering, a team of researchers in the US (Argonne National Laboratory, University of Chicago) employed an electrical signal to periodically alter the magnon vibrational frequency and thereby inducing effective magnon-photon interaction resulting in a microwave-magnonic device with on-demand tunability. The device can control the strength of the photon-magnon interaction at any point as information is being transferred between photons and magnons. It can even […]

Developing smarter, faster machine intelligence with light

Phys.org  December 18, 2020 Optical alternatives to electronic hardware could help speed up machine learning processes by simplifying the way information is processed in a non-iterative way. However, photonic-based machine learning is typically limited by the number of components that can be placed on photonic integrated circuits, limiting the interconnectivity, while free-space spatial-light-modulators are restricted to slow programming speeds. A team of researchers in the US (George Washington University, UCLA, industry) replaced spatial light modulators with digital mirror-based technology, thus developing a system over 100 times faster. The non-iterative timing of this processor, in combination with rapid programmability and massive […]

Engineers improve signal processing for small fiber optic cables

Science Daily  September 16, 2020 A team of researchers in the US (Michigan Technological University, Argonne National Laboratory) explain the quantum and crystallographic origins of a novel surface effect in nonreciprocal optics that improves the processing of optical signals. They found significant differences in the ionic structure between surface and bulk in bismuth-substituted iron garnet materials. They found that the unit cell is elongated normal to the surface, thus enlarging the separation between Fe3+ ions. These ions play a central role in the magneto-optic response of this material. A marked displacement of Fe ions creates gaps at the surface that […]

How lasers can help with nuclear nonproliferation monitoring

Phys.org  April 13, 2020 To study hydrodynamics and evolution of uranium (U) atomic and uranium oxide (UO) molecular emission in filament-produced U plasmas researchers in the US (Pacific Northwest National Laboratory, industry, University of Arizona) performed two-dimensional plume and spectral imaging. The results highlight that filament ablation of U plasmas gives a cylindrical plume morphology with an appearance of plume splitting into slow- and fast-moving components at later times of its evolution. Emission from the slow-moving component shows no distinct spectral features (i.e. broadband-like) and is contributed in part by nanoparticles generated during ultrafast laser ablation. They found U atoms […]

Revealing hidden information in sound waves

Phys.org   November 29, 2018 Sonar arrays are typically designed to record sounds in specific frequency ranges. Sounds with frequencies higher than an array’s intended range may confuse the system. Researchers at the University of Michigan have developed a technique that will allow just about any signal to be shifted to a frequency range where sonar arrays are no longer confused. It mathematically combines any two frequencies within the signal’s recorded frequency range, to reveal information outside that range at a new, third frequency which is the sum or difference of the two input frequencies. The additional information could boost performance […]

Artificial intelligence can predict your personality … simply by tracking your eyes

Eurekalert  July 27, 2018 An international team of researchers (Germany, Australia) used state-of-the-art machine-learning algorithms to demonstrate a link between people’s eye movements and their personality. It reveals whether they are sociable, conscientious or curious, with the algorithm software reliably recognising four of the Big Five personality traits: neuroticism, extroversion, agreeableness, and conscientiousness. The study provides new links between previously under-investigated eye movements and personality traits and delivers important insights for emerging fields of social signal processing and social robotics… read more. Open Access TECHNICAL ARTICLE