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Volume 24, Issue 6
Displaying 1-10 of 10 articles from this issue
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Akira HASEGAWA1996 Volume 24 Issue 6 Pages 631-632
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDownload PDF (151K) -
Masataka NAKAZAWA1996 Volume 24 Issue 6 Pages 633-640
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSCurrent progress on long-distance soliton transmission technologies is summarized, in which the use of erbium-doped fiber amplifiers has been a major breakthrough for the soliton communication. Techniques which can send solitons over unlimited distance are described, in which soliton control in time and frequency domains plays an important role as an optical 3R repeater. Finally, a new soliton transmission technique which employs dispersion allocation is described, which enables us to bring the soliton transmission into a developmental stage.View full abstractDownload PDF (1072K) -
Katsumi IWATSUKI1996 Volume 24 Issue 6 Pages 641-648
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThis paper describes the importance of distributed fiber dispersion and the waveform equalization with optical filtering technique in ultra-high speed and/or ultra-long distance optical soliton transmission.View full abstractDownload PDF (926K) -
Kazuro KIKUCHI1996 Volume 24 Issue 6 Pages 649-655
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn a long-distance optical amplifier chain, the waveform distortion is induced both by the Kerr nonlinearity and the group-velocity dispersion of optical fibers. To cope with this problem, the optical communication system using mid-span optical phase conjugation has been proposed and experimented with. In this paper, after reviewing the methods for combating with such waveform distortion, we describe the principle of the system using optical phase conjugation. The proper design for the amplifier spacing and the dispersion value of transmission fibers is necessary to improve the distortion compensation efficiency. Some examples of system design are shown, and the feasibility of practical optical phase conjugators is briefly discussed.View full abstractDownload PDF (861K) -
Hiroyuki TODA1996 Volume 24 Issue 6 Pages 656-662
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSOptical soliton transmission in a cascaded fiber link is one of the most attractive methods for future optical communications. However, to achieve stable soliton transmission, the amplifier spacing has to be much smaller than the dispersion length, which limits the bit rate for certain amplifier spacing. To overcome this problem, changing dispersion of the fiber in proportion to the local power between the optical amplifiers is effective. This paper introduces the basic idea of the dispersion management in soliton transmission and its application to TDM and WDM soliton transmission.View full abstractDownload PDF (755K) -
Yoichi FUJII1996 Volume 24 Issue 6 Pages 663-669
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSRecent development of soliton technology, “solitonics” is described. New soliton families are introduced, as the coupled soliton, the supersoliton, etc. Novel systems of soliton transmission, such as the coupled transmission, the paired transmission, the phase conjugated transmission, etc. are proposed. These multiplex transmission system are effective to reduce the transmission jitters and to enhance the channel capacity. Switching and logic devices are proposed by using asymmetrical nonlinear coupler. The logic element has a property of AND-OR gates but it cannnot be realized to be small size. The WDM soliton transmission is now very promising for ultra-high capacity communication. The nonlinear coupling between the solitons with different wavelengths are analyzed and a “kidnapping” effect, in which one soliton carries off a part of another soliton.View full abstractDownload PDF (934K) -
Hironobu KIMURA, Kazuhiko HARA, Tomohiro IIJIMA, Takuya NAYUKI, Etsuo ...1996 Volume 24 Issue 6 Pages 670-678
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe lasing performance of acopper vapor laser (CVL) with 60 mm diameter and 2000 mm discharge length has bee nsuccessfully improved by adding Ag and/or Cs atoms. As typical results, 33% increase of output power and wall-plug efficiency has been obtained. The upper laser level is enhanced by the collisional energy transfer from are sponse of Ag atoms to a resonance-excited state of Cuatoms. In addition, the effective relaxation of the lower laser level is appeared due to the collision of the second kind between the metastable Cu atoms and adding Cs atoms.View full abstractDownload PDF (1118K) -
Akira MATSUNAWA, Jong-Do KIM, Seiji KATAYAMA, Tadashi TAKEMOTO1996 Volume 24 Issue 6 Pages 679-688
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe present paper describes spectroscopic characteristics of plume induced in the pulsed YAG laser welding of alloys containing a large amount of volatile elements. The authors have conducted the spectroscopic analyses of laser induced Al-Mg alloys plume in the air and argon atmosphere. In the air environment, the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn, and singly ionized Mg lines, as well as the intense molecular spectra of AlO and MgO formed by chemical reactions of evaporated Al and Mg atoms from the pool surface with oxygen in the air. In argon atmosphere, MgO and AlO spectra vanished, but AlH spectrum was detected. The hydrogen source was presumably hydrogen dissolved in the base metals, water adsorbed on the surface oxide layer, or H2 and H2O in the shielding gas. The resonant lines of Al and Mg were strongly self-absorbed, in particular, self-absorption of the Mg line was predominant. The self-absorption was stronger in the plume of higher Mg content alloys. These results show that the laser induced plume was made of metallic vapor with relatively low temperature and high density.View full abstractDownload PDF (2069K) -
Teturo IZUMITANI, Bo PENG, Kathleen RICHARDSON1996 Volume 24 Issue 6 Pages 689-694
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSSpectroscopic properties of Cr doped silicate and aluminate glasses were compared with Cr: forsterite. Emissions were found at 970nm in silicate glass and 1170nm in aluminate glass. The 970nm emission was attributed to Cr3+4T2 and 1170nm emission to Cr4+3T2. The energy transfer from Cr3+4T1 to Cr4+3T2 and Cr4+3T1 to Cr3+4T2 were found in Cr: forsterite.View full abstractDownload PDF (666K) -
1996 Volume 24 Issue 6 Pages 699
Published: June 30, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDownload PDF (366K)
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