Showing papers in "IEICE Transactions on Electronics in 2018"
31 citations
24 citations
TL;DR: This paper theoretically revisits linear passive two-port systems from the viewpoint of power transfer by generalizing the kQ product as a figure of merit for two- port performance evaluation and extends the theory to a black-box model that represents any kind of powerTransfer channel.
Abstract: This paper theoretically revisits linear passive two-port systems from the viewpoint of power transfer. Instead of using the conventional S21 magnitude, we propose generalizing the kQ product as a figure of merit for two-port performance evaluation. We explore three examples of power transfer schemes, i.e. inductive, capacitive, and resistive channels. Starting from their voltage-current equations, the kQ formula is analytically derived for each scheme. The resultant formulas look different in appearance but are all physically consistent with ωM/R, which stems from the original definition of kQ product in a primitive transformer. After comprehensively learning from the three examples, we finally extend the theory to a black-box model that represents any kind of power transfer channel. In terms of general two-port Z-parameters, useful mathematical expressions are deduced for the optimum load, input impedance, and maximum power transfer efficiency. We also supplement the theory with helpful graphics that explain how the generalized kQ behaves as a function of the circuit parameters. key words: extended ESR, generalized kQ, maximum efficiency
24 citations
TL;DR: The effectiveness of recently-reported techniques for extended-dynamic-range CISs is clarified and the FoM defined by (noise)2(power)/(intrascene dynamic range)(pixel-rate) separately for low/middle and high pixel-rate regions well explains the frontline of the CIS’ performance in all the pixel rates.
Abstract: This paper reviews architectures and topologies for column-parallel analog-to-digital converters (ADCs) used for CMOS image sensors (CISs) and discusses the performance of CISs using columnparallel ADCs based on figures-of-merit (FoM) with considering noise models which behave differently at low/middle and high pixel-rate regions. Various FoM considering different performance factors are defined. The defined FoM are applied to surveyed data on reported CISs using columnparallel ADCs which are categorized into 4 types; single slope, SAR, cyclic and delta-sigma ADCs. The FoM defined by (noise)2(power)/(pixel-rate) separately for low/middle and high pixel-rate regions well explains the frontline of the CIS’ performance in all the pixel rates. Using the FoM defined by (noise)2(power)/(intrascene dynamic range)(pixel-rate), the effectiveness of recently-reported techniques for extended-dynamic-range CISs is clarified. key words: CMOS image sensor, column-parallel ADC, cyclic ADC, deltasigma modulation, single-slope ADC, SAR ADC, figure of merit
23 citations
TL;DR: Novel SV modulator and receiver circuits realized on monolithic InP platforms are proposed and demonstrated and should be attractive candidate in realizing low-cost monolithic transceivers for SVM formats.
Abstract: To meet the demand for continuous increase in data traffic, full usage of polarization freedom of light is becoming inevitable in the next-generation optical communication and datacenter networks. In particular, Stokes-vector modulation direct-detection (SVM-DD) formats are expected as potentially cost-effective method to transmit multi-level signals without using costly coherent transceivers in the short-reach links. For the SVM-DD formats to be practical, both the transmitter and receiver need to be substantially simpler, smaller, and lower-cost as compared to coherent counterparts. To this end, we have recently proposed and demonstrated novel SV modulator and receiver circuits realized on monolithic InP platforms. With compact non-interferometric configurations, relatively simple fabrication procedures, and compatibility with other active photonic components, the proposed devices should be attractive candidate in realizing low-cost monolithic transceivers for SVM formats. In this paper, we review our approaches as well as recent progresses and provide future prospects. key words: photonic integrated circuits, optical polarization, optical modulator, optical receivers, indium phosphide
20 citations
TL;DR: A single-end-access configuration of this strain and temperature sensing system is developed, which enhances the degree of freedom in embedding the sensors into structures and shows that the temperature sensitivity is significantly enhanced with increasing temperature toward ∼70◦C, which is close to the glass-transition temperature of the core polymer.
Abstract: We review the recent advances on strain and temperature sensing techniques based on multimodal interference in perfluorinated (PF) graded-index (GI) polymer optical fibers (POFs). First, we investigate their fundamental characteristics at 1300 nm. When the core diameter is 62.5 μm, we obtain strain and temperature sensitivities of −112 pm/με and +49.8 nm/◦C, the absolute values of which are, by simple calculation, approximately 13 and over 1800 times as large as those in silica GI multimode fibers, respectively. These ultra-high strain and temperature sensitivities probably originate from the unique PF polymer used as core material. Subsequently, we show that the temperature sensitivity (absolute value) is significantly enhanced with increasing temperature toward ∼70◦C, which is close to the glass-transition temperature of the core polymer. When the core diameter is 62.5 μm, the sensitivity at 72◦C at 1300 nm is 202 nm/◦C, which is approximately 26 times the value obtained at room temperature and >7000 times the highest value previously reported using a silica multimode fiber. Then, we develop a single-end-access configuration of this strain and temperature sensing system, which enhances the degree of freedom in embedding the sensors into structures. The light Fresnel-reflected at the distal open end of the POF is exploited. The obtained strain and temperature sensitivities are shown to be comparable to those in two-endaccess configurations. Finally, we discuss the future prospects and give concluding remarks. key words: polymer optical fibers, perfluorinated polymer, modal interference, strain sensing, temperature sensing
18 citations
TL;DR: This paper summarizes the current research results targeting SFQ microprocessors and onchip cache architectures and comes to the conclusion that a bit-parallel gate-level pipeline architecture is the best solution for SFQ designs.
Abstract: CMOS microprocessors are limited in their capacity for clock speed improvement because of increasing computing power, i.e., they face a power-wall problem. Single-flux-quantum (SFQ) circuits offer a solution with their ultra-fast-speed and ultra-low-power natures. This paper introduces our contributions towards ultra-high-speed cryogenic SFQ computing. The first step is to design SFQ microprocessors. From qualitatively and quantitatively evaluating past-designed SFQ microprocessors, we have found that revisiting the architecture of SFQ microprocessors and on-chip caches is the first critical challenge. On the basis of cross-layer discussions and analysis, we came to the conclusion that a bit-parallel gate-level pipeline architecture is the best solution for SFQ designs. This paper summarizes our current research results targeting SFQ microprocessors and onchip cache architectures. key words: single flux quantum (SFQ), cryogenic computing, microprocessor, cache memory, Josephson junction, low-power, high-performance, energy-efficient
15 citations
13 citations
TL;DR: A radiation-hardened Flip-Flop with stacked transistors based on the Adaptive Coupling Flip- Flop with low power consumption in a 65 nm FDSOI process and higher radiation hardness than a conventional DFF and ACFF is proposed.
Abstract: We propose a radiation-hardened Flip-Flop (FF) with stacked transistors based on the Adaptive Coupling Flip-Flop (ACFF) with low power consumption in a 65 nm FDSOI process. The slave latch in ACFF is much weaker against soft errors than the master latch. We design several FFs with stacked transistors in the master or slave latches to mitigate soft errors. We investigate radiation hardness of the proposed FFs by α particle and neutron irradiation tests. The proposed FFs have higher radiation hardness than a conventional DFF and ACFF. Neutron irradiation and α particle tests revealed no error in the proposed AC Slave-Stacked FF (AC SS FF) which has stacked transistors only in the slave latch. We also investigate radiation hardness of the proposed FFs by heavy ion irradiation. The proposed FFs maintain higher radiation hardness up to 40 MeV-cm2/mg than the conventional DFF. Stacked inverters become more sensitive to soft errors by increasing tilt angles. AC SS FF achieves higher radiation hardness than ACFF with the performance equivalent to that of ACFF. key words: single event effect, soft error, α particle, neutron, heavy ion, FDSOI, flip-flop, low-power consumption
11 citations
8 citations
TL;DR: Numerical calculation results reveal that the logic state of RQFP can be changed quasi-statically and adiabatically, or thermodynamically reversibly, and that the energy dissipation required for RZFP to perform a logic operation can be arbitrarily reduced.
Abstract: We have been investigating reversible quantum-fluxparametron (RQFP), which is a reversible logic gate using adiabatic quantum-flux-parametron (AQFP), toward realizing superconductor reversible computing. In this paper, we review the recent progress of RQFP. Followed by a brief explanation on AQFP, we first review the difference between irreversible logic gates and RQFP in light of time evolution and energy dissipation, based on our previous studies. Numerical calculation results reveal that the logic state of RQFP can be changed quasi-statically and adiabatically, or thermodynamically reversibly, and that the energy dissipation required for RQFP to perform a logic operation can be arbitrarily reduced. Lastly, we show recent experimental results of an RQFP cell, which was newly designed for the latest cell library. We observed the wide operation margins of more than 4.7 dB with respect to excitation currents. key words: reversible computing, adiabatic logic, QFP
TL;DR: Development of Small Dielectric Lens for Slot Antenna Using Topology Optimization with Normalized Gaussian Network with Normalization Gaussian network is developed.
Abstract: Title Development of Small Dielectric Lens for Slot Antenna Using Topology Optimization with Normalized Gaussian Network Author(s) Itoh, Keiichi; Nakajima, Haruka; Matsuda, Hideaki; Tanaka, Masaki; Igarashi, Hajime Citation IEICE transactions on electronics, E101.C(10), 784-790 https://doi.org/10.1587/transele.E101.C.784 Issue Date 2018-10 Doc URL http://hdl.handle.net/2115/72063 Rights copyright©2018 IEICE Type article File Information e101-c_10_784.pdf
TL;DR: This paper presents low-noise amplifier (LNA)-less 300GHz CMOS receivers that operate above the NMOS unity-power-gain frequency, fmax, and shows the potential of the moderatefmax CMOS technology for ultrahigh-speed THz wireless communications.
Abstract: This paper presents low-noise amplifier (LNA)-less 300GHz CMOS receivers that operate above the NMOS unity-power-gain frequency, fmax. The receivers consist of a down-conversion mixer with a doubleror tripler-last multiplier chain that upconverts an LO1/n signal into 300 GHz. The conversion gain of the receiver with the doubler-last multiplier is −19.5 dB and its noise figure, 3-dB bandwidth, and power consumption are 27 dB, 27 GHz, and 0.65 W, respectively. The conversion gain of the receiver with the tripler-last multiplier is −18 dB and its noise figure, 3-dB bandwidth, and power consumption are 25.5 dB, 33 GHz, and 0.41 W, respectively. The receivers achieve a wireless data rate of 32 Gb/s with 16QAM. This shows the potential of the moderatefmax CMOS technology for ultrahigh-speed THz wireless communications. key words: Receiver, CMOS integrated circuits, terahertz, frequency conversion mixers, frequency multipliers, amplifiers, quadrature amplitude modulation
TL;DR: Two types of couplers are proposed: a pair of grating coupler with metal mirrors for multi-layer distance coupling and taper-type directional coupler for neighboring layer distance coupling.
Abstract: To realize three-dimensional (3D) optical interconnection on large-scale integration (LSI) circuits, layer-to-layer couplers based on Si-photonics platform were reviewed. In terms of optical cross talk, more than 1 μm layer distance is required for 3D interconnection. To meet this requirement for the layer-to-layer optical coupler, we proposed two types of couplers: a pair of grating couplers with metal mirrors for multi-layer distance coupling and taper-type directional couplers for neighboring layer distance coupling. Both structures produced a high coupling efficiency with relatively compact (∼100 μm) device sizes with a complementary metal oxide semiconductor (CMOS) compatible fabrication process. key words: Si photonics, 3D optical interconnection, layer-to-layer coupler, grating
TL;DR: It is experimentally confirmed that there is no excess insertion loss due to the shuffling structure in the 3-D shuffling waveguide, which will be a promising component to achieve high bandwidth density wiring for on-board optical interconnects.
Abstract: This paper introduces a formation method for 3dimensional 6 ch.× 6 ch. shuffling structures with graded-index (GI) circular core in a multimode polymer optical waveguide for optical printed circuit boards (OPCBs) using a unique photomask-free fabrication technique named the Mosquito method. The interchannel pitch of the fabricated waveguides is 250 μm, where all the channels consist of both horizontal and vertical bending structures and the last 6 channels in parallel cross over the first 6 channels. We also report 3-dimensional S-shaped polymer waveguides. In the S-shaped waveguides, the first and last 6 channels with both horizontal and vertical core bending composing the above 3-dimensional shuffling waveguide are separated, in order to evaluate the effect of over-crossing on the loss. It is experimentally confirmed that there is no excess insertion loss due to the shuffling structure in the 3-D shuffling waveguide. The evaluated crosstalk of the 3-D shuffling waveguide is lower than −30 dB. The 3-D shuffling waveguide proposed in this paper will be a promising component to achieve high bandwidth density wiring for on-board optical interconnects. key words: polymer waveguides, 3-dimensional channel-shuffling structure, multimode GI circular core, optical printed circuit boards (OPCBs)
TL;DR: A water leakage monitoring system that gathers acoustic data of water pipes using wireless communication technology and identifies the sound of water leakage using machine leaning technology and radio propagation from underground manholes using the 920 MHz band is presented.
Abstract: This paper presents a water leakage monitoring system that gathers acoustic data of water pipes using wireless communication technology and identifies the sound of water leakage using machine leaning technology. To collect acoustic data effectively, this system combines three types of data-collection methods: drive-by, walk-by, and static. To design this system, it is important to ascertain the wireless communication distance that can be achieved with sensors installed in a basement. This paper also reports on radio propagation from underground manholes made from reinforced concrete and resin concrete in residential and commercial areas using the 920 MHz band. We reveal that it is possible to design a practical system that uses radio communication from underground sensors. key words: IoT wireless access networks, 920 MHz Band, Propagation from underground manholes, IoT services
TL;DR: A proof-of-concept transmission experiment confirmed that the hybrid modulation laser has a larger dispersion tolerance than conventional directly modulated lasers due to the negative frequency chirp originating from intra-cavity-loss modulation.
Abstract: Frequency chirp of a semiconductor laser is controlled by using hybrid modulation, which simultaneously modulates intra-cavity loss and injection current to the laser. The positive adiabatic chirp of injection-current modulation is compensated with the negative adiabatic chirp created by intra-cavity-loss modulation, which enhances the chromatic-dispersion tolerance of the laser. A proof-of-concept transmission experiment confirmed that the hybrid modulation laser has a larger dispersion tolerance than conventional directly modulated lasers due to the negative frequency chirp originating from intra-cavity-loss modulation. key words: dispersion tolerance, frequency chirp, frequency response, semiconductor lasers
TL;DR: Transistor operation in a vertical p-MoS2/n-HfS2 van der Waals (vdW) heterostructure configuration for the first time is experimentally demonstrated and the effect of atmospheric exposure on the subthreshold slope (SS) of the HfS 2/ MoS2 transistor is studied.
TL;DR: In this paper, a new method was proposed to estimate accurate internal quantum efficiency (IQE) values by simultaneous photoluminescence (PL) and photo-acoustic (PA) measurements, and demonstratively evaluated the IQE values for various GaN samples.
Abstract: Internal quantum efficiency (IQE) is usually estimated from temperature dependence of photoluminescence (PL) intensity by assuming that the IQE at cryogenic temperature is unity. III-nitride samples, however, usually have large defect density, and the assumption is not necessarily valid. In 2016, we proposed a new method to estimate accurate IQE values by simultaneous PL and photo-acoustic (PA) measurements, and demonstratively evaluated the IQE values for various GaN samples. In this study, we have applied the method to InGaN quantum-well active layers and have estimated the IQE values and their excitation carrier-density dependence in the layers. key words: internal quantum efficiency, recombination, PAS, PL
TL;DR: interesting phenomena and device applications in phase-shifted superconducting systems are presented, and various possibilities for developing electrically and magnetically controllable 0 and π junctions are presented; these possibilities are expected to be useful for future devices.
Abstract: The physics and applications of superconducting phase shifts and their control in superconducting systems are reviewed herein. The operation principle of almost all superconducting devices is related to the superconducting phase, and an efficient control of the phase is crucial for improving the performance and scalability. Furthermore, employing new methods to shift or control the phase may lead to the development of novel superconducting device applications, such as cryogenic memory and quantum computing devices. Recently, as a result of the progress in nanofabrication techniques, superconducting phase shifts utilizing π states have been realized. In this review, following a discussion of the basic physics of phase propagation and shifts in hybrid superconducting structures, interesting phenomena and device applications in phase-shifted superconducting systems are presented. In addition, various possibilities for developing electrically and magnetically controllable 0 and π junctions are presented; these possibilities are expected to be useful for future devices. key words: superconductivity, superconducting spintronics, π junction, phase shift, Josephson junction
TL;DR: Applications in optical communication are studied in terms of the inline operation and amplification of a sophisticated modulation format in phase-sensitive amplifiers using periodically poled LiNbO3.
Abstract: Recent advances in phase-sensitive amplifiers (PSAs) using periodically poled LiNbO3 are reviewed. Their principles of operation and distinct features are described. Applications in optical communication are studied in terms of the inline operation and amplification of a sophisticated modulation format. Challenges for the future are also discussed. key words: optical amplifier, lithium niobate, quasi-phase marching, optical communication