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

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


Papers
1. Hiroki Fukuda, Kenta Yamaguchi, Takeshi Kuboki, Kazutoshi Kato, High-speed and long-term wavelength stabilization of tunable distributed amplification distributed feedback laser after laser activation with feedforward and feedback control, Japanese Journal of Applied Physics, Part 2: Letters, 10.7567/JJAP.57.08PD04, 57, 8, 08PD04, 2018.07, To manage recent exponentially increasing data traffic, optical-to-optical burst switching and packet switching systems have been attracting much attention because they do not require an optical-to-electrical and an electrical-to-optical conversions. These systems require high-speed optical switches with a large number of input/output ports. As a candidate for the optical switch, we have focused on the combination of wavelength tunable lasers and an arrayed waveguide grating router, and studied the tunable distributed amplification distributed feedback (TDA-DFB) lasers for the optical switch. Previously, our derived feedforward current control achieved high-speed wavelength switching at a single laser in six-arrayed TDA-DFB lasers. For larger-scale optical switching, wavelength switching from a laser to another in an array is required to cover a wide tunable range. In this study, we develop a novel current control model and successfully stabilize the wavelength immediately after laser activation, which would enable high-speed switching between different lasers. Furthermore, we demonstrate the combination of feedforward and feedback controls for high-speed switching with long-term stability..
2. Hiroki Fukuda, Kenta Yamaguchi, Takeshi Kuboki, Kazutoshi Kato, High-speed and long-term wavelength stabilization of tunable distributed amplification distributed feedback laser after laser activation with feedforward and feedback control, Japanese Journal of Applied Physics, 10.7567/JJAP.57.08PD04, 57, 8, 2018.08, To manage recent exponentially increasing data traffic, optical-to-optical burst switching and packet switching systems have been attracting much attention because they do not require an optical-to-electrical and an electrical-to-optical conversions. These systems require high-speed optical switches with a large number of input/output ports. As a candidate for the optical switch, we have focused on the combination of wavelength tunable lasers and an arrayed waveguide grating router, and studied the tunable distributed amplification distributed feedback (TDA-DFB) lasers for the optical switch. Previously, our derived feedforward current control achieved high-speed wavelength switching at a single laser in six-arrayed TDA-DFB lasers. For larger-scale optical switching, wavelength switching from a laser to another in an array is required to cover a wide tunable range. In this study, we develop a novel current control model and successfully stabilize the wavelength immediately after laser activation, which would enable high-speed switching between different lasers. Furthermore, we demonstrate the combination of feedforward and feedback controls for high-speed switching with long-term stability..
3. Takeshi Kuboki, Tomoki Sadakiyo, Wee Sang Park, Haruichi Kanaya, Impedance-matched planar-antenna-integrated high-efficiency push-pull power amplifier with center-tapped transformer for 5 GHz wireless communication, Sensors and Materials, 10.18494/SAM.2018.2025, 30, 12, 2969-2978, 2018.12, We present a highly efficient power amplifier (PA) with an impedance-matched planar antenna. An impedance-matching network including inductors and capacitors is a common and essential practice for wireless communication systems; however, efficiency degradation at a matching network is a serious issue. We implement a matching block into a planar antenna and integrate a PA with the impedance-matched planar antenna. The impedance-matched antenna and PA are applied to a wireless transmitter for the 5 GHz band in a 0.18 mm CMOS. The proposed integrated PA has a power-added efficiency (PAE) of 15.7% in linear operation and a maximum PAE of 30.7%..
4. Etalon-filter-based mode hop detection for wavelength tunable lasers.
5. Prompt Stabilization of Optical Wavelength at Tunable Laser after Starting Oscillation.
6. Demonstration of Optical-to-Wireless Media Conversion by Using Photomixing and Cross Gain Modulation.
7. Proposal and Demonstration of Chromatic Dispersion Measurement at Optical Waveguide Devices and Application for Controlling Phase of THz Wave.
8. Jun Tsuboi, Takeshi Kuboki, Kazutoshi Kato, Wide-capture-range, high-precision wavelength stabilization within ±50MHz for flexible-grid wavelength division multiplexing by photomixing technique, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.7567/JJAP.55.08RB10, 55, 8, 2016.08, The lasers for the flexible-grid wavelength division multiplexing (WDM) system are required to have high precision of wavelength stability. Previously, we proposed the wavelength-controlling system of the distributed feedback laser diode (DFB-LD) with the photomixing technique and a microwave filter to precisely measure the optical frequency error from the target value. To enlarge the wavelength-capture range, we improve the system to detect the wavelength error with two different microwave filters in parallel. Experimental results show that the wavelength-capture range is extended up to 4GHz while the wavelength error is still kept within +50MHz..
9. C-14-24 Wavelength Stabilization of the DFB Laser by Counting the Frequency of the Beat Signal with Reference Lightwaves.
10. C-14-25 Carrier Frequency Generation by Mach-Zehnder Interferometric Phase Stabilization with Wavelength Selective Filter.
11. C-3-2 Reduction of Wavelength Switching time of Telecom Lasers by Feedforward Control.
12. C-3-7 Wavelength Stabilization of DFB-LD with High Accuracy and Wide Capture Range.
13. Proposal of Feedforward/Feedback Controller and Demonstration of Prompt Wavelength Switching of the Wavelength Tunable Laser.
14. C-3-44 Wavelength Stabilization by Current Control of the DFB Laser within +/- 50MHz using the Beat Signal with Reference Lightwaves.
15. C-12-65 A Study on Jitter Lowering of Ring-VCO with Inductive Peaking.
16. C-12-8 High Speed Design Method of D-FF Circuit Focused on Transistor Size in Sub-100nm CMOS.
17. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, Area-Effective Inductive Peaking with Interwoven Inductor for High-Speed Laser-Diode Driver for Optical Communication System, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, 10.1587/transfun.E95.A.479, E95A, 2, 479-486, 2012.02.
18. Takeshi Kuboki, Yusuke Ohtomo, Akira Tsuchiya, Keiji Kishine, Hidetoshi Onodera, Area-effective inductive peaking with interwoven inductor for high-speed laser-diode driver for optical communication system, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E95.A.479, E95-A, 2, 479-486, 2012.02, This paper presents an area-effective bandwidth enhancement technique using interwoven inductors. Inductive peaking is a common practice for bandwidth enhancement, however the area overhead of inductors is a serious issue. We implement six or four inductors into an interwoven inductor. Furthermore parasitics of the inductors can be reduced. The proposed inductor is applied to a laser-diode driver in a 0.18 μm CMOS. Compared to conventional shunt-peaking, the proposed circuit achieves 1.6 times faster operation and 60% reduction in power consumption under the condition for the same amount of data transmission and the LD driving current. The interwoven inductor can reduce the circuit area by 26%. Parasitic capacitance in interwoven inductor is discussed. Simulation results reveal that line-to-line capacitance is a significant factor on bandwidth degradation..
19. C-12-39 Relationship of crosstalk noise from underlying interconnects and structures of on-chip differential transmission-line.
20. C-12-44 Effect of crosstalk noise from underlying interconnects on on-chip differential transmission-line.
21. Takeshi Kuboki, Akira Tsuchiya, Hidetoshi Onodera, Low-power design of CML driver for on-chip transmission-lines using impedance-unmatched driver, IEICE TRANSACTIONS ON ELECTRONICS, 10.1093/ietele/e90-c.6.1274, E90C, 6, 1274-1281, 2007.06.
22. Takeshi Kuboki, Akira Tsuchiya, Hidetoshi Onodera, Low-Power Design of CML Driver for On-Chip Transmission-Lines Using Impedance-Unmatched Driver, IEICE Transactions on Electronics, 90, 6, 1274-1281, 2007.06, This paper proposes a design technique to reduce the power dissipation of CML driver for on-chip transmission-lines. CML drivers can operate at higher frequency than conventional static CMOS logic drivers. On the other hand, the power dissipation is larger than that of CMOS static logic drivers. The proposed method reduces the power dissipation by using an impedance-unmatched driver instead of the conventional impedance-matched driver. Measurement results show that the proposed method reduces the power dissipation by 32% compared with a conventional design at 12.5Gbps..
23. Low-power design of CML driver for on-chip transmission-lines using impedance-unmatched driver.