Review
Chemistry, Physical
Yonatan Pugachov, Moria Gulitski, Dror Malka
Summary: This paper reviews recent advancements in all-optical memory components, focusing on various types of all-optical flip-flops based on photonic crystal structures. The study explores key materials and crucial properties of all-optical flip-flops, and discusses their advantages for advancing optical computing and optical memory systems.
Article
Computer Science, Information Systems
Bomin Joo, Bai-Sun Kong
Summary: This paper proposes conditional-bridging flip-flops (CBFFs) to address the issues of power consumption and unreliable operation in conventional flip-flops. The proposed flip-flops feature fully static operation, reduced switching power consumption, and reliable operation down to near-threshold voltage. The experiments demonstrate significant improvements in terms of power consumption, latency, and power-delay product compared to conventional flip-flops.
Article
Computer Science, Information Systems
Filippo Minnella, Jordi Cortadella, Mario R. Casu, Mihai T. Lazarescu, Luciano Lavagno
Summary: Flip-flops are commonly used in synchronous circuits, but designs based on latches can be more efficient in terms of frequency and area. The Mix & Latch methodology proposes a single clock tree and a mixed distribution of positive-and negative-edge-triggered flops, and positive-and negative-level-sensitive latches to increase the operating frequency of synchronous digital circuits. The technique is validated using a 28 nm CMOS FDSOI technology, achieving significant improvements in operating frequency and circuit area.
Article
Engineering, Electrical & Electronic
Atousa Jafari, Mohsen Raji, Behnam Ghavami
Summary: This paper proposes a transistor-level restructuring technique to improve the timing reliability of pulsed FFs, with experimental results showing significant improvement under different process variation and operation time.
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
(2021)
Article
Engineering, Electrical & Electronic
Chaoran Huang, Aashu Jha, Thomas Ferreira de Lima, Alexander N. Tait, Bhavin J. Shastri, Paul R. Prucnal
Summary: The integrated device based on microring resonator assisted Mach-Zehnder interferometer offers high programmability and switching contrast for nonlinear optical signal processing. It can serve as a multi-purpose optical processor with functionalities such as signal contrast improvement and pulse carving. The device shows potential for system-level applications in optical interconnects and photonic neural networks.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Sergei Masis, Sergey Hazanov, Nir Alfasi, Oleg Shtempluck, Eyal Buks
Summary: The study uses optical detection of magnetic resonance to investigate dipolar interaction in diamond between nitrogen-vacancy color centers of different crystallographic orientations and substitutional nitrogen defects. Optical measurements of resonant spin flip-flips and flip-flops between different spin ensembles in diamond are demonstrated. The findings could aid in optimizing cross-polarization protocols to enhance the sensitivity of diamond-based detectors.
Article
Multidisciplinary Sciences
Qi-Ming Chen, Michael Fischer, Yuki Nojiri, Michael Renger, Edwar Xie, Matti Partanen, Stefan Pogorzalek, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Summary: By measuring the non-equilibrium dynamics of a superconducting Duffing oscillator, we experimentally reconcile the classical and quantum descriptions and explain the classically regarded steady states as quantum metastable states. Our results reveal a smooth quantum state evolution behind a sudden dissipative phase transition and provide insights into the intriguing phenomena in driven-dissipative systems.
NATURE COMMUNICATIONS
(2023)
Article
Computer Science, Hardware & Architecture
Gyounghwan Hyun, Taewahn Kim
Summary: This article addresses the two critical limitations of conventional methods for allocating state retention storage in power gated circuits and proposes solutions. It also introduces an independent set-based algorithm for maximally extracting nonconflict pairs from circuits, as well as a new design of 2-bit MBRFF to further reduce power consumption in sleep mode.
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS
(2021)
Article
Engineering, Electrical & Electronic
Sekeon Kim, Sehee Lim, Dong Han Ko, Tae Woo Oh, Seong-Ook Jung
Summary: Nonvolatile processors (NVPs) are promising for energy-constrained internet-of-things applications. This study presents two nonvolatile SAFFs with significantly low sequencing overhead and low operating energy.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2023)
Article
Chemistry, Physical
Naohito Urakami, Yuka Sakuma, Toshikaze Chiba, Masayuki Imai
Summary: This study found that lipid flip-flops can induce shape changes in small unilamellar vesicles (SUVs) under specific conditions, depending on the lipid types and distributions. The deformation pathway of binary vesicles is influenced by negative spontaneous curvature lipids, while vesicle division is affected by the flip-flop rates of various lipids.
Article
Computer Science, Hardware & Architecture
Francesco Centurelli, Giuseppe Scotti, Gaetano Palumbo
Summary: This article presents a static frequency divider design based on FMCML, utilizing optimized design strategies. Validation in 28-nm CMOS technology shows power consumption and frequency performance for high-speed and minimum PDP designs at 12 GHz with 74 mu W and 10 GHz with 53 mu W, respectively.
IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS
(2021)
Article
Computer Science, Information Systems
Se Keon Kim, Tae Woo Oh, Sehee Lim, Dong Han Ko, Seong-Ook Jung
Summary: Nonvolatile systems with NVFFs are gaining attention for their energy efficiency in energy-harvesting devices and battery-operated IoT applications. FeFET is a promising NVM, and the proposed FeFET-out and -in NVFFs achieve better performance.
Article
Multidisciplinary Sciences
Qi Shen, Jian-Yu Guan, Ji-Gang Ren, Ting Zeng, Lei Hou, Min Li, Yuan Cao, Jin-Jian Han, Meng-Zhe Lian, Yan-Wei Chen, Xin-Xin Peng, Shao-Mao Wang, Dan-Yang Zhu, Xi-Ping Shi, Zheng-Guo Wang, Ye Li, Wei-Yue Liu, Ge-Sheng Pan, Yong Wang, Zhao-Hui Li, Jin-Cai Wu, Yan-Yan Zhang, Fa-Xi Chen, Chao-Yang Lu, Sheng-Kai Liao, Juan Yin, Jian-Jun Jia, Cheng-Zhi Peng, Hai-Feng Jiang, Qiang Zhang, Jian-Wei Pan
Summary: Networks of optical clocks are important for navigation, redefining time units, and gravitational tests. However, achieving a global-scale optical network with comparable performance requires the dissemination of time and frequency over a long-distance free-space link with matching instability. Previous attempts at high precision dissemination of time and frequency did not extend beyond dozens of kilometers. In this study, we report successful time-frequency dissemination over a free-space link of 113 km with an offset of 6.3 x 10(-20)+/- 3.4 x 10(-19) and an instability of less than 4 x 10(-19), using key technologies such as high-power frequency combs.
Article
Computer Science, Information Systems
Yaqing Chi, Chang Cai, Ze He, Zhenyu Wu, Yahao Fang, Jianjun Chen, Bin Liang
Summary: The study found that the DICE structure enhances radiation tolerance, but there are still challenges in facing SEUs, as clock signals and data patterns can affect the mitigation of hardened DFFs. Evaluating SEUs for different types of irradiation can help eliminate overestimation of SEU tolerance.
Article
Optics
Miaodi Guo, Haifeng Li, Ning Li, Yajie Wu
Summary: We propose a scheme for tunable coherent perfect absorption (CPA) and near-perfect reflection (near CPR) in a three-level A-type atom-cavity system. By utilizing electromagnetically-induced-transparency-type interference induced by a coherent coupling laser, tunable near CPR at two-photon resonance can be achieved. Additionally, we demonstrate that CPA can be switched to the near-CPR regime by adjusting the linear absorption or gain using an incoherent pump field. This research provides a theoretical mechanism for manipulation of perfect absorption and reflection, with potential applications in coherent optical computing and communication.
Article
Optics
Surajit Bose, Oliver Melchert, Stephanie Willms, Ihar Babushkin, Uwe Morgner, Ayhan Demircan, Govind P. Agrawal
Summary: The frequency dependence of the nonlinear parameter plays a crucial role in the evolution of femtosecond solitons inside photonic crystal fibers. The conventional approach based on the self-steepening effect is not appropriate for fibers with two zero-dispersion wavelengths, and higher-order nonlinear terms are necessary for realistic modeling of nonlinear phenomena in PCFs. These terms not only affect the Raman-induced wavelength shift of a soliton but also impact its shedding of dispersive radiation.
Article
Optics
Junchi Zhang, W. R. Donaldson, Govind P. Agrawal
Summary: This study investigates the impact of the finite rise time of a spatiotemporal boundary inside a dispersive medium on the reflection and refraction of optical pulses. It is found that the frequency range over which reflection can occur decreases as the rise time increases. Additionally, total internal reflection can occur even for boundaries with long rise times, suggesting the possibility of realizing spatiotemporal waveguides through cross-phase modulation with pump pulses of relatively long rise and fall times.
Article
Optics
Saif A. Al Graiti, Drew N. Maywar
Summary: This study presents a mathematical model that demonstrates how a linear polarizer can transform the shape of an optical-power hysteresis curve. The model considers the generalized Malus' law and optimization using a polarization controller, and the results are applicable to various all-optical signal processing applications.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
M. R. Maafa, D. N. Maywar
Summary: This article demonstrates a technique to selectively double or quadruple the frequency of a microwave signal using a commercial modulator. The frequency multiplication is achieved by controlling the synchronization of two optical signals through the manipulation of optical path length. The technique shows high side-tone suppression and low phase noise.
ELECTRONICS LETTERS
(2022)
Review
Optics
Aneesh Sobhanan, Aravind Anthur, Sean O'duill, Mark Pelusi, Shu Namiki, Liam Barry, Deepa Venkitesh, Govind P. Agrawal
Summary: This review article focuses on the fundamentals, broad applications, and importance of semiconductor optical amplifiers (SOAs) in optical communication, especially in optical channels with advanced modulation formats and optical signal processing.
ADVANCES IN OPTICS AND PHOTONICS
(2022)
Article
Optics
Junchi Zhang, William Donaldson, Govind P. Agrawal
Summary: This article investigates the temporal reflection of an optical pulse from a refractive-index barrier created by a short pump soliton in a nonlinear dispersive medium such as an optical fiber. One notable feature is that the soliton's speed continuously changes due to intrapulse Raman scattering, resulting in significant effects on the shape and spectrum of the reflected pulse. Under certain conditions, the reflected pulse can become considerably narrower, exhibiting a phenomenon similar to temporal focusing.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2022)
Article
Optics
Bryce A. Tennant, Drew N. Maywar
Summary: We propose a method to suppress degenerate lasing modes using photonic bandgaps and achieve single-mode distributed feedback lasing. Our experimental results show that this method performs better than the traditional DFB laser structure, and it has potential applications in different material platforms.
Article
Optics
Xiaotong He, Luis Cortes-Herrera, Kwadwo Opong-Mensah, Yi Zhang, Meiting Song, Govind P. Agrawal, Jaime Cardenas
Summary: In this work, the authors demonstrate continuous on-chip optical frequency conversion using an electrically tunable lithium niobate ring resonator. Frequency shifts of up to 14.3 GHz are achieved by adjusting the voltage, allowing dynamic control of light behavior within the cavity.
Article
Optics
Govind P. Agrawal
Summary: Doped and optically pumped GRIN fibers are used to amplify optical beams, improving their spatial quality at the output end. We developed a simple model of the amplification process and solved the resulting equations analytically. The solution showed that the amplifying beam's width oscillates and becomes narrower due to the radial dependence of optical gain. Our simplified approach provides an analytic expression for the damping distance of beam-width oscillations, clarifying the role of various physical parameters.
Article
Optics
Govind P. Agrawal
Summary: This study uses coherence theory to investigate the effect of partial coherence on the focusing of an optical beam by a graded-index (GRIN) lens. The Gaussian-Schell model demonstrates that a partially coherent beam exhibits self-imaging and periodic evolution in a GRIN medium with a parabolic index profile. The spatial coherence of the beam affects a parameter governing the compression of the beam at the focal point. Our results indicate that the size of the focal spot depends on the fraction of the beam's diameter over which coherence persists. Focusing ceases to occur, and the beam may even expand at the focal point of a GRIN lens when this fraction is below 10%.
Article
Optics
Govind P. Agrawal
Summary: A semi-analytic model is proposed to describe the amplification process of Raman amplifiers using graded-index multimode fibers. When the pump beam is much stronger than the signal, it evolves in a self-similar manner and periodically recovers its initial width. The width of the amplified signal satisfies an equation similar to a damped harmonic oscillator, which is used to discuss spatial beam narrowing inside a Raman amplifier. Our simplified approach provides an analytic expression for the damping distance of width oscillations, highlighting the role of various physical parameters.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Optics
Junchi Zhang, William R. Donaldson, Govind P. Agrawal
Summary: We investigated the propagation of optical pulses in a temporal waveguide formed by two solitons in a dispersive nonlinear medium like an optical fiber. Due to intrapulse Raman scattering, the solitons, which are short enough, decelerate and their spectra continuously shift towards the red side. It was found that a probe pulse trapped between the two solitons evolves in a periodic fashion with a blueshift in its spectrum. We developed a coupled-mode theory to explain these changes, which are caused by mode coupling induced by the deceleration of the short solitons, resulting in a curved waveguide. A simplified two-mode model was used to introduce a single parameter that governs the modal coupling and find the condition for the probe pulse to blueshift its spectrum without changing its pulse shape.
Article
Optics
Junchi Zhang, William Donaldson, Govind P. Agrawal
Summary: This study demonstrates the formation of a Raman-induced temporal waveguide by launching short pump and probe pulses inside a photonic crystal fiber. The pump pulse creates a fundamental soliton with continuously changing speed due to the Raman-induced red shift of its spectrum. The spectrum of the probe pulse is blue-shifted to ensure that both pulses move at the same speed and trajectory over the entire length of the fiber. The output wavelengths of the pulses depend on the peak power of the input pump pulses and agree with the predictions based on dispersion data.
Article
Optics
Sergey A. Ponomarenko, Junchi Zhang, Govind P. Agrawal
Summary: We discover a significant temporal shift of the peak of an optical pulse when it is totally internally reflected from a sharp temporal boundary in a uniform and isotropic linear medium. The sign of this temporal shift depends on the group-velocity mismatch between the pulse and the temporal boundary, suggesting the possibility of a delay or advancement of the pulse upon reflection. Our analytical results, validated by numerical simulations, provide insights into the fundamental aspects of wave packet interaction with temporal boundaries in material media.
Article
Optics
Luis Cortes-Herrera, Xiaotong He, Jaime Cardenas, Govind P. Agrawal
Summary: This paper presents a comprehensive theoretical study of energy efficiency in adiabatic frequency conversion (AFC) in an all-pass resonator. The study analyzes the upper limit of energy efficiency using the Cauchy-Schwarz inequality and examines its dependence on input pulse shape.
