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Volume 27, Issue 4
Displaying 1-14 of 14 articles from this issue
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Minoru OBARA1999 Volume 27 Issue 4 Pages 229
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (172K) -
Masataka NAKAZAWA1999 Volume 27 Issue 4 Pages 230
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
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Yoshiaki YAMABAYASHI, Hiromu TOBA, Masataka NAKAZAWA1999 Volume 27 Issue 4 Pages 231-239
Published: April 15, 1999
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSThis paper reviews state-of-the-art technologies that will play important roles in high bit rate transmissionsystems. To take full advantage of fiber capacity, combined multiplexing of WDM (Wavelength Division Multiplexing) and TDM (Time Division Multiplexing) technologies is recommended. Not only device technologies, but also system-side viewpoints are emphasized in order to clarify the differences between TDM and WDM systems. Linear transmission and nonlinear ones, which includes optical soliton systems are comparedfrom such a viewpoint. Short light pulse sources, electrical and optical time-division multiplexing/demultiplexing, timing extraction, dispersion tolerant coding, equalization for second- and third-order dispersionof dispersion-shifted fiber, and optical soliton transmission technologies are described. This paper predictsthat pursuing increased transmission capacity will result in more combined designs of detailed fiberdispersion and transmitted optical signal parameters.View full abstractDownload PDF (2040K) -
Eiichi SANO1999 Volume 27 Issue 4 Pages 240-245
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSUltrahigh-speed integrated-circuit technology is one of the key technologies for achieving ultralarge-capacity optical communication systems. Technological breakthroughs in circuit and packaging design as well as improved transistor performance are needed to reach the over-40-Gbit/s operating region. This paper describes InP-based device, high-speed circuit, and broadband packaging technologies developedto boost the speed of lightwave communication ICs. By using these technologies, we could make 40-Gbit/s lightwave communication ICs. Future prospects and a number of other related technological issues are also addressed.View full abstractDownload PDF (1583K) -
Yoh OGAWA1999 Volume 27 Issue 4 Pages 246-250
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSOptical Time Division Multiplexing (OTDM) is attracting much attention for use in future largecapacity optical communication systems. In such systems, optical pulses with short pulse width, high repetition rate, low timing jitter, and low chirp, are required. This paper reviews ultrafast optical pulse sources, such as modelocked semiconductor lasers, electroabsorption modulators, and mode-locked fiber lasers.View full abstractDownload PDF (939K) -
Katsumi EMURA1999 Volume 27 Issue 4 Pages 251-256
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSThis paper introduces research trends in terabit-per-second (Tb/s) Wavelength Division Multiplexing (WDM) optical transmission technologies that will be indispensable for constructing a next-generation ultra-highcapacity trunk network. First, technologies for improving the WDM spectral efficiency and increasing the optical amplifier bandwidth are introduced in order to increase the total WDM capacity. Then related optical device technologies are briefly introduced, especially ones for fabricating WDM light sources. Finally, technical challenges towards Tb/s transmission over distances of 10, 000 km are mentioned, including RZ pulse-based WDM transmission.View full abstractDownload PDF (1248K) -
Kazuhito TAJIMA, Shigeru NAKAMURA, Yoshiyasu UENO, Junichi SASAKI, Tak ...1999 Volume 27 Issue 4 Pages 257-261
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe demonstrate 200 fs switching and 1.5Tbps demultiplexing with a polarization-discriminating symmetric Mach-Zehnder (PD-SMZ) all-optical switch. Such ultrafast switching was possible, because the switching speed of PD-SMZ is not restricted by slow relaxation time of the highly efficient bandfilling nonlinearity in semiconductors. These results indicate all-optical demultiplexing well exceeding 1 Tbps would be possible. We also report on photonic integration of SMZ, using the Planer Lightwave Circuit technology. With a photonically integrated SMZ, we achieved an extinction ratio better than 12 dB. Its switching speed was limited only by the measurement system in the present experiment, but we anticipate true picosecond switching would be possible.View full abstractDownload PDF (905K) -
Hitoshi MURAI, Makoto SHIKATA, Yukihiro OZEKI1999 Volume 27 Issue 4 Pages 262-267
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSAn alternating dispersion scheme for dispersion managed WDM soliton is proposed over standard fiber line to improve the tolerance of path-average dispersion of the fiber combination. A WDM transmission experiment at 4×20 Gbit/s over 1000 km was successfully demonstrated with the proposed dispersion arrangement.View full abstractDownload PDF (1144K) -
Kazunori SUZUKI, Hirokazu KUBOTA, Eiichi YAMADA, Akio SAHARA, Masataka ...1999 Volume 27 Issue 4 Pages 268-273
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe report 40 Gbit/s soliton transmission field experiments over 1, 000 km in the Tokyo metropolitan optical loop network. The network consists of dispersion-shifted fibers. We employed a dispersion compensation technique to keep the average dispersion at a small constant value of 0.05 ps/km/nm and this resulted in an error-free 5 ps soliton data transmission over 1, 000 km. When in-line synchronous modulation was employed at 680 km, the transmission distance was extended to 1, 360 km.View full abstractDownload PDF (1117K) -
Eiji YOSHIDA, Masataka NAKAZAWA1999 Volume 27 Issue 4 Pages 274-280
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSA stable optical short pulse source with a high repetition rate is very important for realizing future ultrahigh speed optical communication. Of the many potential techniques, an actively mode-locked fiber laser is one of the most attractive sources for generating high quality picosecond pulses at GHz repetition rates. In this paper, we report a regeneratively mode-locked fiber laser which emits a 1-3 ps transform limited pulse at 10 GHz in the 1.53 to 1.55μm wavelength region. This laser can be locked to an external signal by operating a phase-locked loop technique. By using this pulse source and an adiabatic soliton compression technique, a 170 fs pulse train at 10 GHz was generated. Finally, we show the excellent jitter characteristics of the laser.View full abstractDownload PDF (2288K) -
Hiroki YOSHIDA, Kenji YASUFUKU, Yukio SAKAGAMI1999 Volume 27 Issue 4 Pages 281-285
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSIn laser fusion experiments, a nonsupported pellet is desirable for high uniform compression. To realize this, the magnetically suspended pellet (MSP) has been studied. By observing its horizontal motion caused by counterbalance between optical force and magnetic force, the magnetic shape coefficient Km and the specific permeability μm, are verified analytically and experimentally. The optical force is explained in terms of the resultant force of the photon force and the radiometric force.View full abstractDownload PDF (750K) -
Tsuneo KURITA, Tomohiko ONO, Noboru MORITA1999 Volume 27 Issue 4 Pages 286-290
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSThe goal of the research is to construct a laser processing system for the manufacture of stepped shapes. In order to achieve this goal, this study aims to clarify the relationship between the strength of laser processing sound and groove cross-sectional area per pulse when a Q-switched YAG laser beam was applied for laser grooving. The main findings of this study are as follows: 1) The relationship between the strength of the processing sound and groove cross-sectional area per pulse of Q-switched laser beam could be expressed by a straight line on a log-log chart even if the applied laser energies were changed, and 2) The gradient of the straight line showed different values when two types of work materials were processed by a Q-switched YAG laser.View full abstractDownload PDF (1230K) -
Hidetsugu YOSHIDA, Ryosuke KODAMA, Hisanori FUJITA, Yoshiaki KATO, Kun ...1999 Volume 27 Issue 4 Pages 291-297
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe have developed a front-end system to generate a chirped pulse at a wavelength of 1053 nm for a 100 TW glass laser system. The front-end system consists of a passively mode-locked diode-pumped Nd: glass laser, a pulse stretcher and a Ti: Al2O3 regenerative amplifier. The passive mode-locked diode-pumped Nd: fluorophoshate glass laser produced pulses as short as 150 fs at an average power of 100 mW at 1053 nm-1061 nm at a repetition frequency of 99.98 MHz. The TEM00 Ti: Al2O3 regenerative amplifier exhibited a net gain of over 106 at 1053 nm. At long time operation, the output pulse energy is typically 4 mJ, with a power fluctuation of less than ±5% with temperature and humidity control in cavity. No significant gain narrowing was observed in the cavity, resulting in a 1.6 ns chirped pulse that was synchronized with the RF signal of GEKKO XII laser system within a few ps by controlling the oscillator cavity length with a PZT actuator.View full abstractDownload PDF (1476K) -
Takatomo SASAKI1999 Volume 27 Issue 4 Pages 298-302
Published: April 15, 1999
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (888K)
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