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Effects of multi-context information recorded at different regions in holographic polymer-dispersed liquid crystal on optical reconfiguration 査読

Akifumi Ogiwara, Minoru Watanabe

JAPANESE JOURNAL OF APPLIED PHYSICS 55 ( 8 ) 08RG04-1 - 08RG04-6 2016年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IOP PUBLISHING LTD

A holographic polymer-dispersed liquid crystal (HPDLC) memory to record multi-context information for an optically reconfigurable gate array is formed by constructing a laser illumination system to implement successive laser exposures at different small regions in a glass cell filled with LC composites. The context pattern arrangements for circuit information are designed in a 3 x 3 in. 2 photomask by electron beam lithography, and they are recorded as laser interference patterns at nine regions separated in an HPDLC sample by a laser interferometer composed of movable pinhole and photomask plates placed on motorized stages. The multi-context information reconstructed from the different regions in the HPDLC is written to a photodiode array in a gate-array VLSI by switching only the position of laser irradiation using the displacement of the pinhole plate under the control of a personal computer ( PC). The effects of multi-context information recorded at different regions in the HPDLC on optical reconfiguration are discussed in terms of the optical system composed of ORGA VLSI and HPDLC memory. The internal structures in the HPDLC memory formed by multi-context recording are investigated by scanning electron microscopy ( SEM) observation, and the configurations composed of LC and polymer phases are revealed at various regions in the HPDLC memory. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.08RG04

Direct optical communication on an optically reconfigurable gate array 査読

Shinya Furukawa, Ili Shairah Abdul Halim, Minoru Watanabe, Fuminori Kobayashi

2016 FIFTH INTERNATIONAL CONFERENCE ON FUTURE COMMUNICATION TECHNOLOGIES (FGCT) 17 - 20 2016年8月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

As one type of field programmable gate array (FPGA), optically reconfigurable gate arrays (ORGAs) have been undergoing continual development. ORGAs are optoelectronic devices consisting of a holographic memory, a laser array, a programmable gate array. Since the storage capacity of such holographic memory is greater than that of two-dimensional semiconductor memory, an ORGA can accommodate more huge gates and provide higher performance than FPGAs. A programmable gate array of an ORGA has numerous photodiodes that can be reconfigured optically using configuration contexts on a holographic memory. Although the photodiodes are normally used only for a configuration procedure, the photodiodes are useful for direct input of optical communication signals. This paper therefore presents a demonstration of optical communication on ORGA's programmable gate array.

DOI： 10.1109/FGCT.2016.7605065

Demonstrating a Holographic Memory Having 100 Mrad Total-Ionizing-Dose Tolerance 査読

Yoshizumi Ito, Minoru Watanabe, Akifumi Ogiwara

PROCEEDINGS OF 2016 7TH INTERNATIONAL CONFERENCE ON MECHANICAL AND AEROSPACE ENGINEERING, (ICMAE) 377 - 380 2016年7月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Currently, space systems require highly radiation tolerant memory. If memory with high radiation tolerance were available, then shielding of embedded systems for use in space could be reduced or removed, thereby greatly decreasing the weight of such space embedded systems. This study examines the radiation-hardened characteristics of a holographic memory. Using a cobalt 60 gamma radiation source, radiation experiments were conducted for a photopolymer holographic memory. Results show that the holographic memory can function correctly at a 100 Mrad total-ionizing dose. The radiation tolerance of the holographic memory is over 300 times higher than that of an electrically erasable programmable read-only memory (EEPROM). Moreover, this paper shows a demonstration applied for an optically reconfigurable gate array. The configuration procedure could be executed by using the radiation-damaged holographic memory.

DOI： 10.1109/ICMAE.2016.7549569

Radiation tolerance of a MEMS mirror device 査読

Takumi Fujimori, Minoru Watanabe

2016 INTERNATIONAL CONFERENCE ON OPTICAL MEMS AND NANOPHOTONICS (OMN) 1 - 2 2016年7月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper presents experimentally obtained results demonstrating the radiation tolerance of a MEMS mirror device. The radiation tolerance was confirmed as 170 Mrad or higher total-ionizing dose tolerance.

DOI： 10.1109/OMN.2016.7565925

Architecture-Independent Negative Logic Implementation for Optically Reconfigurable Gate Arrays 査読

Takumi Fujimori, Minoru Watanabe

PROCEEDINGS OF 2016 7TH INTERNATIONAL CONFERENCE ON MECHANICAL AND AEROSPACE ENGINEERING, (ICMAE) 381 - 385 2016年7月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Optically reconfigurable gate arrays (ORGAs) comprise a holographic memory, a laser array, and an optically reconfigurable gate array VLSI. According to holographic memory properties, the reconfiguration speed and radiation tolerance of ORGAs depend on the number of bright bits included in a configuration context. This paper therefore proposes a method of reducing the number of bright bits included in a configuration context using negative logic implementation. Since the method is architecture-independent, the method offers the important benefit that it is never necessary to modify the architecture of optically reconfigurable gate array VLSIs. This paper describes experimental demonstrations of the reconfiguration speed and radiation-tolerance advantages of the method.

DOI： 10.1109/ICMAE.2016.7549570

A 180 Mrad Total-Ionizing Dose Experiment for Laser Arrays on Optically Reconfigurable Gate Arrays 査読

K. Akagi, M. Watanabe

25th Annual Single Event Effects (SEE) Symposium 2016年5月

Quality Recovery Method of Interference Patterns Generated From Faulty MEMS Spatial Light Modulators 査読

Minoru Watanabe

JOURNAL OF LIGHTWAVE TECHNOLOGY 34 ( 3 ) 910 - 917 2016年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Currently, microelectromechanical system (MEMS) spatial light modulators (SLMs) with numerous tiny mirrors that are controllable as a binary state are available. Such MEMS spatial light modulators are useful as holographic displays, optical tweezers, optical memories, reconfigurable lenses, etc. Although nonfault devices are always used for such applications, this paper clarifies that even if a part of a MEMS-SLM is faulty, the MEMS-SLM is useful for almost all commercial products related to the applications described above. Moreover, it is useful even as research equipment with a high degree of precision. This paper therefore presents the fault-tolerance analysis results of light intensity, contrast ratio, and spot size of interference pattern generated from a MEMS-SLM to clarify the allowable deteriorations of faulty MEMS-SLMs. Moreover, we propose a recovery method that a faulty MEMS-SLM can be used as a nonfaulty MEMS-SLM by exploiting excess laser power.

DOI： 10.1109/JLT.2015.2483622

Full FPGA Game Machine 査読

Takumi Fujimori, Minoru Watanabe

2016 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE) 431 - 432 2016年1月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Currently, many consumer game machines are based on the operations of processors. However, in the field programmable gate array (FPGA) research field, various FPGA game solvers have been developed recently. The processing speeds of such FPGA game solvers can reach about 1000 times faster than processor-based operations. This paper explains the development of one such FPGA game solvers, the Blokus Duo FPGA solver, and presents discussion of how processors on game machines can be replaced with FPGAs in future consumer game machines.

DOI： 10.1109/ICCE.2016.7430678

Reconfiguration performance recovery on optically reconfigurable gate arrays 査読

Tomoya Akabe, Minoru Watanabe

2016 29TH INTERNATIONAL CONFERENCE ON VLSI DESIGN AND 2016 15TH INTERNATIONAL CONFERENCE ON EMBEDDED SYSTEMS (VLSID) 603 - 604 2016年1月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, radiation-hardened optoelectronic field programmable gate arrays (FPGAs) or optically reconfigurable gate arrays (ORGAs) have been under development. We propose a method of reconfiguration performance recovery for maintaining the gate array performance of ORGAs. We have experimentally demonstrated the recovery of the ORGA configuration speed merely by exploiting excess laser power.

DOI： 10.1109/VLSID.2016.67

Angle-multiplexing recording of circuit information in volume hologram using liquid crystal composites

Akifumi Ogiwara, Yuta Maeda, Minoru Watanabe

Optics InfoBase Conference Papers 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：OSA - The Optical Society

Formation of holographic memory using liquid crystal composites is reported for optically reconfigurable gate arrays. The different circuit information is recorded at four angles by switching the reference beam under the control of motorized stages.

DOI： 10.1364/iprsn.2016.jtu4a.38

Sustainable advantage of a parallel configuration in an optical FPGA 査読

Minoru Watanabe

2015 IEEE/SICE INTERNATIONAL SYMPOSIUM ON SYSTEM INTEGRATION (SII) 807 - 810 2015年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, static random access memory (SRAM)based field programmable gate arrays (FPGAs) are used for various systems. Since such SRAM-based FPGAs are programmable, their use over a long period must accommodate the use of a partly damaged programmable gate array. However, since current FPGAs use a serial configuration line for their configuration and the serial configuration circuit is invariably first broken circuit. Therefore, currently available FPGAs cannot accommodate the use of a partly damaged programmable gate array. However, if a partly damaged programmable gate array could be used, then the lifetime of VLSIs would be increased drastically. To extend the lifetime of programmable devices, FPGA should use a parallel configuration architecture instead of the serial configuration architecture of currently available FPGAs. This paper therefore clarifies the benefits of the parallel configuration architecture on an optically reconfigurable gate array (ORGA) VLSI using the designs of an ORGA-VLSI and a currently available serial-configuration FPGA.

DOI： 10.1109/SII.2015.7405083

Triple modular redundancy on parallel-operation-oriented optically reconfigurable gate arrays 査読

Yoshizumi Ito, Minoru Watanabe

2015 IEEE INTERNATIONAL CONFERENCE ON AEROSPACE ELECTRONICS AND REMOTE SENSING TECHNOLOGY (ICARES) 2015年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, to realize autonomous functions resembling those of humans on space systems, higher-performance embedded systems than those of current space systems are necessary for use in long-distance space missions. Currently, a parallel-operation-oriented optically reconfigurable gate array (ORGA) has been under development. The ORGA can support a nanosecond-order high-speed reconfiguration and high-density implementation of parallel operations. The parallel-operation-oriented ORGA has many programmable gate array layers, which share a common configuration context and increase the number of implementable parallel operations. Therefore, a parallel-operation-oriented ORGA is suitable for hardware acceleration of a software operation on a processor. However, in a space environment, triple modular redundancy (TMR) must be used. Single common configuration memory becomes a weak point for radiation in terms of redundancy. Therefore, we propose a TMR implementation method that is suitable for the parallel-operation-oriented ORGA.

DOI： 10.1109/ICARES.2015.7429829

Total-ionizing-dose tolerance analysis of an optically reconfigurable gate array VLSI

Minoru Watanabe

2015 IEEE International Conference on Aerospace Electronics and Remote Sensing Technology (ICARES) 2015年12月

FPGA Trax Solver based on a Neural Network Design 査読

Takumi Fujimori, Tomoya Akabe, Yoshizumi Ito, Kouta Akagi, Shinya Furukawa, Hiroki Shinba, Aoi Tanibata, Minoru Watanabe

2015 INTERNATIONAL CONFERENCE ON FIELD PROGRAMMABLE TECHNOLOGY (FPT) 260 - 263 2015年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

For research related to field programmable gate arrays (FPGAs), various FPGA game solvers have been developed recently. The FPGA game solver can achieve up to 1,000 times faster processing speeds than processor-based operations. This paper presents one development of such FPGA game solvers: an FPGA Trax Solver based on a neural network design. The speed of the FPGA Trax Solver operations implemented on an FPGA (Arria II GX; Altera Corp.) is over 60 times greater than operation of C++ based software on a personal computer (Vostro 460; Dell Inc.).

DOI： 10.1109/FPT.2015.7393119

Formation of holographic polymer dispersed liquid crystal memory by angle-multiplexing recording for optically reconfigurable gate arrays 査読

Akifumi Ogiwara, Minoru Watanabe

APPLIED OPTICS 54 ( 36 ) 10623 - 10629 2015年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OPTICAL SOC AMER

Formation of holographic polymer-dispersed liquid crystal (HPDLC) memory for an optically reconfigurable gate array is discussed for angle-multiplexing recording by controlling the laser interference exposure in LC composites. The successive laser illumination system to record the various configuration contexts at the specified region and angle in HPDLC memory is constructed by using the combination of a half-mirror and a photomask placed on the motorized stages under the control of a personal computer. The effect of laser exposure energy on the formation of holographic memory is investigated by measuring diffraction intensity as a function of exposure energy during the grating formation process and observing the internal grating structure by scanning electron microscopy. The optical reconfiguration in the gate-array VLSI is executed for configuration contexts of OR and NOR operations shown as logical operators that are reconstructed by laser irradiation at different incident angles for a specified region in the HPDLC memory. (C) 2015 Optical Society of America

DOI： 10.1364/AO.54.010623

Triple modular redundancy on parallel-operation-oriented FPGA architectures for optical communications 査読

Minoru Watanabe

2015 IEEE International Conference on Space Optical Systems and Applications, ICSOS 2015 1 - 4 2015年10月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Institute of Electrical and Electronics Engineers Inc.

Recently, high-speed space optical communication requires real-time hardware operation instead of slow software operation on a processor. For such purposes, field programmable gate arrays (FPGAS) are extremely useful. In such hardware accelerations, a software algorithm is frequently implemented onto an FPGA as a parallel operation. However, in such implementations, many regions of the configuration memory on an FPGA must have common circuit information, but the overlap on the configuration memory can be regarded as wasteful implementation. Therefore, a parallel-operation-oriented FPGA has been proposed to implement parallel operations onto an FPGA efficiently. Such a parallel-operation-oriented FPGA has numerous programmable gate array layers sharing a common configuration context so that the overlap data on the configuration memory of an FPGA can be removed perfectly. However, in space environments, triple modular redundancy must always be used to remove soft errors and the single shared configuration architecture of the parallel-operation-oriented FPGA is the opposite way of such redundancy. To meet those demands, we propose a suitable implementation method of triple modular redundancy (TMR) onto the parallel-operation-oriented FPGA architecture.

DOI： 10.1109/ICSOS.2015.7425070

100 mrad total-ionizing dose tolerance experiment of a laser array 査読

Kouta Akagi, Minoru Watanabe

2015 IEEE International Conference on Space Optical Systems and Applications, ICSOS 2015 1 - 3 2015年10月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Institute of Electrical and Electronics Engineers Inc.

Recently, lasers are being used for space optical communications. However, in a space environment, space radiation is constantly incident to lasers. Therefore, the radiation tolerance analysis of lasers is an important characteristic that must be evaluated. As described in this report, we present radiation experiment results of a semiconductor laser array. This experiment measured the radiation tolerance of the laser array using a Cobalt 60 gamma radiation source. Results show that the laser array stands up to at least 100 Mrad total ionizing dose.

DOI： 10.1109/ICSOS.2015.7425076

Fresnel lens radiation shield for photodiodes 査読

Minoru Watanabe

2015 IEEE International Conference on Space Optical Systems and Applications, ICSOS 2015 1 - 2 2015年10月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Institute of Electrical and Electronics Engineers Inc.

Recently, since space satellites use image sensors and photodiode sensors, their radiation tolerance has become an important concern. In addition, some available space communication systems use a photodiode sensor for communications. However, since such sensors have an aperture without shielding, the total ionizing dose tolerance of the sensors becomes so weak that the radiation tolerance becomes lower than that of other embedded components. This paper therefore presents a proposal of a Fresnel lens radiation shield for use with photodiodes. A Fresnel lens can increase the light sensitivity and radiation tolerance of a photodiode.

DOI： 10.1109/ICSOS.2015.7425088

Effect of Laser Exposure Condition on Formation of Holographic Memory by Angle-multiplexing Recording using Liquid Crystal composites 査読

Akifumi Ogiwara, Minoru Watanabe

2015 20TH MICROOPTICS CONFERENCE (MOC) 1 - 2 2015年10月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

The effect of laser exposure condition on the formation of holographic polymer-dispersed liquid crystal (HPDLC) memory by the angle-multiplexing recording is discussed. The successive laser illumination system to record the various configuration contexts at the different region and angle in HPDLC memory is constructed by controlling the laser interference exposure in liquid crystal (LC) composites and the optical equipment using the motorized stages.

DOI： 10.1109/MOC.2015.7416433

Investigating the radiation tolerance of a laser array for an optically reconfigurable gate array 査読

Kouta Akagi, Minoru Watanabe

2015 20TH MICROOPTICS CONFERENCE (MOC) 1 - 2 2015年10月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Optically reconfigurable gate arrays (ORGAs) have been developed to realize radiation-hardened field programmable gate arrays (FPGAs). An ORGA consists of a laser array, a holographic memory, and a programmable gate array VLSI. Since the configuration of an ORGA is a parallel configuration, damage to a configuration circuit or a component does not affect configuration procedures on other configuration circuits. Therefore, even if almost all look-up tables (LUTs) malfunction because of radiation, the remaining functional LUTs can be programmed and used, whereas the serial configuration of FPGAs does not allow the use of a partly failed gate array. However, to achieve higher radiation tolerance of a programmable gate array than that of an FPGA in ORGA architecture, the radiation tolerances of a laser array and a holographic memory must be sufficiently higher than that of the part of a programmable gate array VLSI. Since the radiation tolerance of a holographic memory has already been confirmed as sufficiently higher than that of a programmable gate array VLSI, this paper presents a radiation tolerance investigation of a laser array on an optically reconfigurable gate array. Experiments using Co60 gamma radiation have demonstrated that a laser array has a greater than 20 Mrad total ionizing dose tolerance.

DOI： 10.1109/MOC.2015.7416484

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