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 […]
Tag Archives: Optical signal processing
New optical switch could lead to ultrafast all-optical signal processing
Phys.org August 1, 2022 The weak native nonlinearity of most nanophotonic platforms has imposed barriers for the use of optical nonlinear functions for applications in integrated photonics, including all-optical information processing, photonic neural networks, and on-chip ultrafast light sources, by necessitating large driving energies, high-Q cavities, or integration with other materials with stronger nonlinearity. A team of researchers in the US (Caltech, Cornell University) has effectively utilized the strong and instantaneous quadratic nonlinearity of lithium niobate nanowaveguides for the realization of cavity-free all-optical switching. By simultaneous engineering of the dispersion and quasi-phase matching, they designed and demonstrated a nonlinear splitter […]
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 […]
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 […]
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 […]
Team closes in on ‘holy grail’ of room temperature quantum computing chips
Phys.org September 18, 2019 Researchers at the Stevens Institute of Technology have coaxed photons into interacting by firing a laser beam into a racetrack-shaped microcavity carved into a sliver of crystal. As the laser light bounces around the racetrack, its confined photons interact with one another, producing a harmonic resonance that causes some of the circulating light to change wavelength. They boosted its efficiency by using a chip made from lithium niobate on insulator. They used an ion-milling tool to etch a tiny racetrack. The team has already identified ways to increase their Q-factor by a factor of at least […]