Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Takeshi Kuboki Last modified date:2019.06.26

Assistant Professor / Department of Electronics / Faculty of Information Science and Electrical Engineering


Presentations
1. Ming Che, Takeshi Kuboki, Kazutoshi Kato, Mitigating nonlinearity for VLC with CAP modulation, ICEVLC2019, 2019.03.
2. Takeshi Kuboki, Ryo Takigawa, Kazutoshi Kato, Analysis of Adhesive Layer for Lithium Niobate-on-insulator Waveguides on Silicon Wafer with Room-temperature Bonding Method, MOC2018, 2018.10.
3. Younjin Kim, Takeshi Kuboki, Kazutoshi Kato, Monolithically Integrated Photonics Device for Terahertz Wave Generation, MOC2018, 2018.10.
4. Hiroki Fukuda, Shunta Kono, Takeshi Kuboki, Kazutoshi Kato, Wavelength Switching Method Accounting for Nonlinearity of Tunable Distributed Amplification DFB laser, MOC2018, 2018.10.
5. Ming Che, Takeshi Kuboki, Kazutoshi Kato, Adaptive Equalizer Based on Sign-Data LMS for Carrierless Amplitude and Phase Modulation in Multipath Visible Light Communication, MOC2018, 2018.10.
6. Hiroki Fukuda, Kenta Yamaguchi, Takeshi Kuboki, Kazutoshi Kato, Fast wavelength stabilization of tunable laser after starting laser oscillation, 22nd Microoptics Conference, MOC 2017, 2018.01, For fast wavelength switching within the full available wavelength range of the tunable laser array, we investigated a wavelength stabilizing method after switching on the injection current to the laser's active layer. Experimental results demonstrated that our feedback controller dramatically reduced wavelength switching time from 800 μs to 2.0 μs..
7. Masataka Gohara, Ryoga Kimura, Kenta Yamaguchi, Takeshi Kuboki, Kazutoshi Kato, Linearizer for wavelength sweep at tunable DBR-LD and linearity evaluation of sweep, 22nd Microoptics Conference, MOC 2017, 2018.01, We constructed the linear wavelength sweeping system with 2-μm-band distributed Bragg reflector laser for the second-harmonic-detection wavelength modulation spectroscopy. Using our devised linearity evaluation method with a germanium etalon filter, we experimentally confirmed that the nonlinearity of the laser can be efficiently compensated..
8. Yusuke Yamanaka, Younjin Kim, Takeshi Kuboki, Kazutoshi Kato, Optical-to-wireless media conversion by utilizing cross gain modulation at semiconductor optical amplifier, 22nd Microoptics Conference, MOC 2017, 2018.01, We devise an optical-to-wireless media conversion method by XGM at the SOA aiming for a future use at a THz-wave access. We investigate the XGM characteristics and the performance of our proposed media conversion method. We configure the media-converted data transmission system and demonstrate an error free transmission..
9. Ming Che, Takeshi Kuboki, Kazutoshi Kato, Proposal of cost-efficient and low-complexity platform for software defined visible light communication, 22nd Microoptics Conference, MOC 2017, 2018.01, With the increasing popularity of LED lighting and a growing demand for bandwidth in wireless communication, the visible light communication (VLC) is one of the promising scheme for addressing the bottleneck in the emerging broadband access networks. For research in the field of VLC focused on solutions of contradiction between massive available bandwidth and limited modulation bandwidth of LED, the purpose of this paper is to design an VLC experiment platform with characteristics of high flexibility and rapid productization. As a result, this platform not only expand the concept of software defined communication, but has the advantage of simple structure and low cost..
10. Yusuke Yamanaka, Takeshi Kuboki, Kazutoshi Kato, Proposal of THz phase control system utilizing chromatic dispersion at optical device and its feasibility demonstration, 2017 Opto-Electronics and Communications Conference, OECC 2017 and Photonics Global Conference, PGC 2017, 2017.11, We propose a novel THz wave phase control system consisting of an optical device whose chromatic dispersion changes the phase difference between two lightwaves for photomixing. Our devised Mach-Zehnder modulation technique reveals the feasibility of full-range THz wave phase control with the semiconductor phase modulator..
11. Yusuke Yamanaka, Takeshi Kuboki, Kazutoshi Kato, Proposal of THz Phase Control System Utilizing Chromatic Dispersion at Optical Device and Its Feasibility Demonstration, 2017.08.
12. Kenta Yamaguchi, Yudai Tatsumoto, Ryoga Kimura, Takeshi Kuboki, Kazutoshi Kato, Sub-millisecond wavelength switching of tunable DFB laser array (TLA) with injection current control, 2016 International Semiconductor Laser Conference, ISLC 2016, 2016.12, For the purpose of sub-millisecond wavelength switching, the feedforward current control technique was applied to the DFB laser. At the switching from 191.2 THz to 191.0 THz, our designed controller successfully reduced the wavelength switching time of the tunable DFB laser array down to 800 μs..
13. Ryoga Kimura, Yudai Tatsumoto, Hirokazu Onji, Takeshi Kuboki, Kazutoshi Kato, Internal-wavelength-locker based feedforward/feedback co-operative wavelength control for 100 ns wavelength switching, The 21st Microoptics Conference, 2016.10.
14. Jun Tsuboi, Takeshi Kuboki, Kazutoshi Kato, Optical frequency stabilization within ±20MHz of distributed feedback laser controlled by novel feedback algorithm, The 21st Microoptics Conference, 2016.10.
15. Kenta Yamaguchi, Yudai Tatsumoto, Ryoga Kimura, Takeshi Kuboki, Kazutoshi Kato, Sub-millisecond Wavelength Switching of Tunable DFB Laser Array (TLA) with Injection Current Control, The 25th International Semiconductor Laser Conference (ISLC2016), 2016.07.
16. Jun Tsuboi, Takeshi Kuboki, Kazutoshi Kato, Wavelength stabilization within 0.05 GHz with photo-mixing technique and laser current controlling, 20th Microoptics Conference, MOC 2015, 2016.02, The lasers for the WDM system with the flexible grid need to have highly accurate wavelength tuning and stability. Instead of using optical filters, we propose the microwave photonics approach with photo-mixing technique and the laser current controlling. Experimental results show that the optical frequency is stabilized with the accuracy of 0.05GHz..
17. Ryoga Kimura, Yudai Tatsumoto, Takeshi Kuboki, Kazutoshi Kato, Internal-wavelength-locker based feedforward/feedback co-operative wavelength control for 100 ns wavelength switching, 2016.
18. Jun Tsuboi, Takeshi Kuboki, Kazutoshi Kato, Wavelength stabilization within 0.05 GHz with photomixing technique and laser current controlling, The 20th MICROOPTICS CONFERENCE (MOC '15), 2015.10.
19. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 25-Gb/s LD Driver with Area-Effective Inductor in a 0.18um CMOS, The 18th Asia and South pacific Design Automation Conference (ASP-DAC2013), 2013.01.
20. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 25-Gb/s LD driver with area-effective inductor in a 0.18-μm CMOS, 2013 18th Asia and South Pacific Design Automation Conference, ASP-DAC 2013, 2013, This paper presents high-speed and area-efficient laser-diode driver with interwoven inductor in a 0.18-μm CMOS. We interweave ten peaking inductors for area-effective implementation as well as performance enhancement. Interwoven inductor can not only achieve area-efficiency but also tune frequency characteristic. Mutual inductances of interwoven inductor enhance bandwidth and suppress group delay dispersion. The test chip area is 0.32 mm2 and the maximum operating speed is 25 Gb/s..
21. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 16Gb/s Area-Efficient LD Driver with Interwoven Inductor in a 0.18um CMOS, The 17th Asia and South Pacific Design Automation Conference (ASP-DAC2012), 2012.01.
22. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 16Gb/s area-efficient LD driver with interwoven inductor in a 0.18μm CMOS, 17th Asia and South Pacific Design Automation Conference, ASP-DAC 2012, 2012, This paper presents the fastest laser-diode driver with interwoven peaking inductor in 0.18μm CMOS. Six and four inductors are interwoven into two sets of inductors for area-effective implementation as well as performance enhancement. The operation speed enhancement of the proposed circuit is achieved by tuning mutual inductances of interwoven inductors. The circuit area is 0.34-mm 2 and the maximum operating speed is 16-Gb/s..
23. Akira Tsuchiya, Takeshi Kuboki, Yusuke Ohtomo, Keiji Kishine, Shigekazu Miyawaki, Makoto Nakamura, Hidetoshi Onodera, Bandwidth Enhancement for High Speed Amplifier Utilizing Mutually Coupled On-Chip Inductors, International SoC Design Conference (ISOCC2011), 2011.11.
24. Akira Tsuchiya, Takeshi Kuboki, Yusuke Ohtomo, Keiji Kishine, Shigekazu Miyawaki, Makoto Nakamura, Hidetoshi Onodera, Bandwidth enhancement for high speed amplifier utilizing mutually coupled on-chip inductors, 8th International SoC Design Conference 2011, ISOCC 2011, 2011, This paper discusses bandwidth enhancement technique for high speed amplifier. Inductive peaking is a common practice for bandwidth enhancement, however the area occupied by on-chip inductors is a heavy disadvantage. We utilize mutually coupled inductors for effective inductive peaking. A Laser-Diode (LD) driver for optical communication system is designed in a 0.18μm CMOS. Measurement results show that the mutually coupled inductor can achieve 16Gbps operation and 26% area reduction compared to conventional shunt peaking..
25. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 16Gbps Laser-Diode Driver with Interwoven Peaking Inductors in 0.18um CMOS, IEEE Custom Integrated Circuit Conference (CICC2010), 2010.09, 集積回路において大きな面積を占めるインダクタの小型設計を提案した。一対の差動構成のインダクタを一箇所にまとめて配置する巻き込み型インダクタを提案し、従来よりも回路面積を削減することが可能となる。また、従来手法ではインダクタの面積が大きいため、回路を結ぶ配線が長大化するために寄生素子による性能低下が見られていたが、巻き込み型インダクタによってインダクタの面積を削減できるため、寄生素子を最小にでき、回路の動作速度向上を図ることが出来る。0.18umCMOSによる試作回路で実証を行い、回路面積を30%削減、動作速度を1.6倍に向上できることを確認した。.
26. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, A 16Gbps laser-diode driver with interwoven peaking inductors in 0.18-μm CMOS, 32nd Annual Custom Integrated Circuits Conference - The Showcase for Circuit Design in the Heart of Silicon Valley, CICC 2010, 2010, A laser-diode (LD) driver with interwoven mutually-coupled peaking inductors for high-speed optical networks is presented. Six and four inductors are interwoven into two sets of inductors for area-effective implementation as well as performance enhancement. The proposed circuit is fabricated in CMOS 0.18-μm process. The circuit area is 0.34mm2 and the maximum operating speed is 16Gbps. Compared to a conventional LD driver in 0.18-μm CMOS, the proposed circuit achieves 1.6 times faster operation, 26% smaller area with 60% reduction in power consumption under the condition for the same amount of data transmission and the LD driving current..
27. Takeshi Kuboki, Akira Tsuchiya, Hidetoshi Onodera, A 10Gbps/channel On-Chip Signaling Circuit with an Impedance-Unmatched CML Driver in 90nm CMOS Technology, The 12th Asia and South Pacific Design Automation Conference (ASP-DAC2007), 2007.01.
28. Takeshi Kuboki, Akira Tsuchiya, Hidetoshi Onodera, A 10Gbps/channel on-chip signaling circuit with an impedance-unmatched CML driver in 90nm CMOS technology, ASP-DAC 2007 - Asia and South Pacific Design Automation Conference 2007, 2007, An on-chip signaling system consists of a CML driver, a differential transmission-line and a CML receiver is fabricated. We developed an impedance-unmatched driver for power reduction. The impedance-unmatched driver reduces the tail current of the CML buffer by tuning the load resistance. The designed circuit achieves 3mm, 10Gbps/channel on-chip signal transmission and the impedance-unmatched driver saves the energy per bit by 21% compared with a conventional impedance-matched driver..
29. Akira Tsuchiya, Takeshi Kuboki, Hidetoshi Onodera, Low-Power Design of CML Drivers for On-Chip Transmission-Lines, The 13th Workshop on Synthesis And System Integration of Mixed Information technologies (SASIMI2006), 2006.04.