M. Kawasako, T. Watanabe, T. Nagayama, and S. Fukushima, "Scalability of multi-stage nested Mach-Zehnder interferometer optical switch with phase generating couplers," Advances in Science, Technology and Engineering Systems Journal, vol. 7, no. 4, pp. 140-146, August 2022.
K. Tasaki, M. Tokumaru, T. Watanabe, T. Nagayama, and S. Fukushima, "Nested Mach-Zehnder interferometer optical switch with phase generating couplers," Japanese Journal of Applied Physics, vol. 59, no. SO, SOOB04, August 2020.
S. Shimada, T. Watanabe, T. Nagayama, and S. Fukushima, "Design of arrayed-waveguide optical switch employing window function for crosstalk reduction," Japanese Journal of Applied Physics, vol. 58, no. SJ, SJJB03, August 2019.
K. Ueda, Y. Mori, H. Hasegawa, H. Matsuura, K. Ishii, H. Kuwatsuka, S. Namiki, T. Watanabe, and K. Sato, "Fast optical circuit switch for intra-datacenter networking," IEICE Transactions on Communications, vol. E100-B, no. 10, pp. 1740-1746, October 2017.
K. Ueda, Y. Mori, H. Hasegawa, K. Sato, and T. Watanabe, "Large-scale and simple-configuration optical switch enabled by asymmetric-port-count sub-switches," IEEE Photonics Journal, vol. 8, no. 2, 0601610, April 2016.
K. Ueda, Y. Mori, H. Hasegawa, K. Sato, and T. Watanabe, "Large-scale optical-switch prototypes utilizing cyclic arrayed-waveguide gratings for datacenters," Journal of Lightwave Technology, vol. 34, no. 2, pp. 608-617, January 2016.
S. Takashina, H. Ishida, M. Niwa, Y. Mori, H. Hasegawa, K. Sato, and T. Watanabe, "Experimental verification of highly-scalable OXC that consists of subsystem-modular express switch part and multicast-switch-based add/drop part enabling total throughput of 314 Tbps," Optics Express, vol. 23, no. 11, pp. 14796-14805, June 2015.
S. Takashina, Y. Mori, H. Hasegawa, K. Sato, and T. Watanabe, "Wavelength-tunable filters utilizing arrayed waveguide gratings for colorless/directionless/contentionless optical signal drop in ROADMs," IEEE Photonics Journal, vol. 7, no. 1, 7100511, February 2015.
T. Watanabe, S. Sohma, and S. Kamei, "Low-loss wavelength routing optical switch consisting of small matrix switch and cyclic arrayed-waveguide gratings for colorless add/drop," Japanese Journal of Applied Physics, vol. 53, no. 8S2, 08MB02, July 2014.
K. Sato, H. Hasegawa, T. Niwa, and T. Watanabe, "A large-scale wavelength routing optical switch for data center networks," IEEE Communications Magazine, vol. 51, no. 9, pp. 46-52, September 2013.
H. Ono, T. Watanabe, K. Suzuki, A. Mori, T. Takahashi, and T. Sakamoto, "Wide-range variable gain fiber amplifier with erbium-doped fiber switching," Journal of Lightwave Technology, vol. 31, no. 12, pp. 1965-1972, June 2013.
T. Ban, H. Hasegawa, K. Sato, T. Watanabe, and H. Takahashi, "A novel large-scale OXC architecture and an experimental system that utilizes wavelength path switching and fiber selection," Optics Express, vol. 21, no. 1, pp. 469-477, January 2013.
T. Niwa, H. Hasegawa, K. Sato, T. Watanabe, and H. Takahashi, "A large port count wavelength routing optical switch that consists of cascaded small-size cyclic arrayed waveguide gratings," IEEE Photonics Technology Letters, vol. 24, no. 22, pp. 2027-2030, November 2012.
T. Niwa, H. Hasegawa, K. Sato, T. Watanabe, H. Takahashi, and M. Okuno, "Novel wavelength tunable filter offering multi-stage selection for colorless, directionless, and contentionless ROADMs," IEICE Electronics Express, vol. 9, no. 16, pp. 1297-1303, August 2012.
Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, T. Kataoka, T. Watanabe, and Y. Ishii, "Experimental demonstration of multi-degree colorless, directionless, contentionless ROADM for 127-Gbit/s PDM-QPSK transmission system," Optics Express, vol. 19, no. 26, pp. B1-B11, December 2011.
K. Seno, K. Suzuki, N. Ooba, T. Watanabe, M. Itoh, S. Mino, and T. Sakamoto, "50-wavelength channel-by-channel tunable optical dispersion compensator using combination of AWG and bulk grating," IEEE Photonics Technology Letters, vol. 22, no. 22, pp. 1659-1561, November 2010.
K. Seno, N. Ooba, K. Suzuki, T. Watanabe, K. Watanabe, and S. Mino, "Tunable optical dispersion compensator consisting of simple optics with arrayed waveguide grating and flat mirror," IEEE Photonics Technology Letters, vol. 21, no. 22, pp. 1701-1703, November 2009.
M. Okada, J. Kani, T. Watanabe, and N. Yoshimoto, "An optimal investment strategy for tunable, pluggable, and tunable pluggable optical transceivers in static DWDM networks," IEEE/OSA Journal of Optical Communications and Networking, vol. 1, no. 1, pp. 3-16, June 2009.
T. Shibata, M. Okuno, T. Goh, T. Watanabe, M. Yasu, M. Itoh, M. Ishii, Y. Hibino, A. Sugita, and A. Himeno, "Silica-based waveguide-type 16×16 optical switch module incorporating driving circuits," IEEE Photonics Technology Letters, vol. 15, no. 9, pp. 1300-1302, September 2003.
N. Ooba, T. Watanabe, S. Toyoda, T. Kurihara, and M. Hikita , "Polymeric optical waveguide devices based on thermo-optic effect," KIEE International Transactions on Electrophysics and Application, vol. 12-C, no. 2, pp. 91-95, 2002.
T. Watanabe, F. Kano, S. Kuwano, H. Suzuki, and M. Koga, "Scale expansion of transparent photonic transport network based on distributed Raman amplification," IEEE Photonics Technology Letters, vol. 12, no. 10, pp. 1420-1422, October 2000.
T. Watanabe, N. Sakaida, H. Yasaka, F. Kano, and M. Koga, "Transmission performance of chirp-controlled signal using semiconductor optical amplifier," Journal of Lightwave Technology, vol. 18, no. 8, pp. 1069-1077, August 2000.
K. Inoue and T. Watanabe, "Influence of modulation bandwidth on fiber transmission using an electroabsorption modulator," IEICE Transactions on Communications, vol. E82-B, no. 5, pp. 773-775, May 1999.
T. Watanabe, S. Hayashida, and S. Imamura, "Vibrational overtone absorption of side chain in silicone at 1.55 μm wavelength band," Japanese Journal of Applied Physics, vol. 38, part 2, no. 3B, pp. L318-L319, March 1999.
T. Watanabe, H. Yasaka, N. Sakaida, and M. Koga, "Waveform shaping of chirp-controlled signal by semiconductor optical amplifier using Mach-Zehnder frequency discriminator," IEEE Photonics Technology Letters, vol. 10, no. 10, pp. 1422-1424, October 1998.
T. Watanabe, N. Sakaida, H. Yasaka, and M. Koga, "Chirp control of optical signal using phase modulation in semiconductor optical amplifier," IEEE Photonics Technology Letters, vol. 10, no. 7, pp. 1027-1029, July 1998.
T. Watanabe, N. Ooba, S. Hayashida, T. Kurihara, and S. Imamura, "Polymeric optical waveguide circuits formed using silicone resin," Journal of Lightwave Technology, vol. 16, no. 6, pp. 1049-1055, June 1998.
T. Watanabe, N. Ooba, Y. Hida, and M. Hikita, "Influence of humidity on refractive index of polymers for optical waveguide and its temperature dependence," Applied Physics Letters, vol. 72, no. 13, pp. 1533-1535, March 1998.
T. Watanabe, M. Hikita, M. Amano, Y. Shuto, and S. Tomaru, "Vertically stacked coupler and serially grafted waveguide: Hybrid waveguide structures formed using an electro-optic polymer," Journal of Applied Physics, vol. 83, no. 2, pp. 639-649, January 1998.
T. Watanabe, N. Ooba, Y. Hida, S. Hayashida, T. Kurihara, and S. Imamura, "Digital thermooptic switch formed using silicone resin waveguides," Japanese Journal of Applied Physics, vol. 36, part 2, no. 12B, pp. L1672-L1674, December 1997.
T. Watanabe, Y. Inoue, A. Kaneko, N. Ooba and T. Kurihara, "Polymeric arrayed-waveguide grating multiplexer with a wide tuning range," Electronics Letters, vol. 33, no. 18, pp. 1547-1548, August 1997.
Y. Hida, N. Ooba, R. Yoshimura, T. Watanabe, M. Hikita, and T. Kurihara, "Influence of humidity on transmission in a Y-branch thermo-optic switch composed of deuterated fluoromethacrylate polymer waveguides," Electronics Letters, vol. 33, no. 7, pp. 626-627, March 1997.
Y. Shuto, T. Watanabe, S. Tomaru, I. Yokohama, M. Hikita, and M. Amano, "Quasi-phase-matched second harmonic generation in diazo-dye-substituted polymer channel waveguides," IEEE Journal of Quantum Electronics, vol. 33, no. 3, pp. 349-357, March 1997.
M. Usui, M. Hikita, T. Watanabe, M. Amano, S. Sugawara, S. Hayashida, and S. Imamura, "Low-loss passive polymer optical waveguides with high environmental stability," Journal of Lightwave Technology, vol. 14, no. 10, pp. 2338-2343, October 1996.
S. Tomaru, T. Watanabe, M. Hikita, M. Amano, Y. Shuto, I. Yokohama, T. Kaino, and M. Asobe, "Quasi-phase-matched second harmonic generation in a polymer waveguide with a periodic poled structure," Applied Physics Letters, vol. 68, no. 13, pp. 1760-1762, March 1996.
T. Watanabe, M. Amano, and S. Tomaru, "Second-order optical nonlinearities of an electrooptic polymer containing a thiazole ring and its use in single-mode waveguide fabrication," Japanese Journal of Applied Physics, vol. 33, part 2, no. 12A, pp. L1683-L1685, December 1994.
T. Watanabe, M. Amano, M. Hikita, Y. Shuto, and S. Tomaru, "Novel 'serially grafted' connection between functional and passive polymer waveguides," Applied Physics Letters, vol. 65, no. 10, pp. 1205-1207, September 1994.
T. Watanabe, T. Kubo, K. Ishikawa, H. Takezoe, and A. Fukuda, "Multiphonon Raman scattering enhanced by resonance with band gap Ag luminescence state in trans-polyacetylene," Japanese Journal of Applied Physics, vol. 33, part 2, no. 1A, pp. L48-L51, January 1994.
T. Kubo, T. Watanabe, T. Nishioka, H. Takezoe, and A. Fukuda, "Blurring and broadening of reflection spectra due to structural and alignment changes of conjugated chains caused by isomerization and stretching in trans-polyacetylene," Japanese Journal of Applied Physics, vol. 31, part 1, no. 10, pp. 3372-3376, October 1992.
T. Watanabe, T. Kubo, H. Takezoe, and A. Fukuda, "Luminescence and multiphonon Raman scattering excited at exciton-forming vibronic absorption subbands in trans-polyacetylene," Japanese Journal of Applied Physics, vol. 31, part 2, no. 2A, pp. L102-L105, February 1992.
T. Kubo, T. Tsuji, T. Watanabe, T. Fukuda, H. Takezoe, and A. Fukuda, "Photocurrent excitation spectra observed with Au-Al heteroelectrodes biased reversely and reflection spectra in trans-polyacetylene," Japanese Journal of Applied Physics, vol. 30, no. 3B, pp. L500-L503, March 1991.