The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
Volume 22, Issue 4
Displaying 1-13 of 13 articles from this issue
  • Yoshihiro OHTSUKA
    1994 Volume 22 Issue 4 Pages 225
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
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  • Kenji KAWANO
    1994 Volume 22 Issue 4 Pages 226-234
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    This paper desribes a proceudure for calculating the coupling efficiencybetween two Gaussian beams with an emphasis on laser-diode light to single-mode fiber coupling. First, the concept of ray matrices is discussed and the ray matrices for lenses are derived. Second, spotsizesand the beam waist positions of transformed beams are calculated. Third, coupling efficiencies between two Gaussian beams are obtained in a general form. Finally, coupling characteristics are disscussed for various lens systems.
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  • Etsuko ISHIKAWA, Hisayoshi TORATANI
    1994 Volume 22 Issue 4 Pages 235-244
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Lasings in various wavelengths have been widely observed in fiber laser in both pulse and CW modes. In this article, a history of research on fiber laser materials and somerecent progressin fiber laser are reviewed.
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  • Satoshi TANAKA
    1994 Volume 22 Issue 4 Pages 245-252
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The art of the optical fiber sensors is outlined briefly. The characteristics of the polarizationmaintaining single-mode fibers (PMSF) are described from the view point of the interferometricfiber-optic sensors.The PMSF is useful for devising the optical heterodyne polarimetricfiber-coil deformation sensor immune from temperature perturbations. The performance ofthe sensor is presented.
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  • Kazuo HOTATE
    1994 Volume 22 Issue 4 Pages 253-264
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Research and development of Fiber Optic Gyros are described.Interferometer fiber opticgyro, I-FOG for short, is now in the stage of practical applications. Car navigation system, rocket launching, gyro-compas for seeking north, and other applications have been developed. Open-loop configuration is mainly used in the above applications. On the other hand, closedloopconfiguration, which can meet the specification for high grade air craft navigation, hasalso been developed. The second type, resonator fiber optic gyro: R-FOG, is attractive becausethe length of the sensing fiber coil can be shortened to be less than 10m. Noise characterizationhas beem carried out. Fiber optic ring laser gyro, F-RLG is also promissing, inwhich Brillouin scattering in the fiber resonator produces laser oscillation. This type may havea possibility to provide quite a simple configuration.
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  • Kiyoshi KUROSAWA
    1994 Volume 22 Issue 4 Pages 265-275
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    This paper describes a review concerning research and development of optical fiber sensorsfor high voltage electric power apparatus. Firstly, advantages of optical fiber sensing techniquefor monitoring parameters in high voltage power apparatus are explained. Then several examplesof research and of developed devices are introduced in the field of current measurement, voltage measurement, corona discharge detection, and methods for cllection of signals frommultiple sensors.
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  • Kazuhiro OKAMOTO
    1994 Volume 22 Issue 4 Pages 276-283
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Fiber optic related technology enables us to measure temperature distribution along entirelength of optical fiber over several kilometers. This newly developed system is completelydifferent from conventional electrical sensors in that it uses optical fiber itself as a sensor. Thesystem measures temperature distribution by detecting Raman scattered light intensity usingoptical time domain reflectometry-OTDR-method.
    In this paper, we first explain principle of this unique sensing system, and then discuss relationbetween the system's performance and performance of laser light source which is one ofthe most important devices of the system. Also experimental results are shown for each applicablelasers. It became clear that a system using 850nm laser diode is effective for short distancemeasurement while high power, longer wavelength light source must be engaged to measurelonger distance.
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  • Yoshikazu MATSUDA
    1994 Volume 22 Issue 4 Pages 284-291
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The gas detection is an important area of application for fiber sensors. In intrinsic fiber sensors, the fibers are used as sensor element. In the intrisic sensors, the development of whatmay be called a sensor fiber is the principal concern. For gas detection, three types of fibersensor have been studied.
    This report reviews fiber sensors for gas detection from the standpoint of interaction lightwave and gas substances.
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  • Minoru YOSHIDA, Toshikazu GOZEN, Hiroyuki TANAKA
    1994 Volume 22 Issue 4 Pages 292-301
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The optical fiber amplifier allows O/O conversion for direct optical amplification instead ofthe conventional O/E and E/O conversion.
    The amplifier for 1. 55 μm optical signal is compactly composed by Er3+ -doped fiber andother optical components. Amplification and oscillation properties of the amplifier are mainlydependent on the Er3+ doping concentration, the co-dopant, fiber length, and performance of the pumping power source. An optimized fiber, for use within the optical amplifier, has a gainof 40dB and a conversion efficiency of 85% from the incident pumping power to the amplifiedsignal power. Amplification properties also depend on the characteristics of the optical signal.
    With these advantages, the amplifier has brought expandability and flexibility to opticalcommunication systems, making great impact on optical communications. It is applicable topost-amplifiers for enhancing optical signal output, low-noise pre-amplifiers to improve thesensitivity of the signal receiver, in-line amplifier transmission lines and multi-wavelength signalsystems. It is also expected for wider use in long-haul transmission systems, subscriber systems, and future soliton communications.
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  • Shouichi OGITA, Haruhisa SODA
    1994 Volume 22 Issue 4 Pages 302-313
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    High power semiconductor lasers, emitting at 1.48 μm or 0.98 μm are strongly required forpumping Er3+ doped optical fiber amplifiers used in the optical fiber transmission systems. Inthis paper, we review various semiconductor laser structures developed to achieve high outputpower, good fiber coupling, and high reliability. We also present the recent progress in highpower semiconductor lasers based on the strained-layer quantum well structures, including ournewly developed, 100-mW-output, high power semiconductor laser modules emitting at1.48 μm.
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  • Akira HASEGAWA
    1994 Volume 22 Issue 4 Pages 314-320
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    There is an increased interest in the communication system based on the optical soliton ofthe light wave envelope in a fiber. In fact soliton systems have achieved record error-freetransmission both in speed and distance in fibers. This paper reviews the physics of optical sblitonsand characteristics of soliton based communication systems.
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  • Hiroshi ITO, Noriaki GOTO, Shinichi IMAI
    1994 Volume 22 Issue 4 Pages 321-328
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The output power of YAG laser can be transmitted through a silica fiber, which gives rise tohigh flexibility in the laser processing system. In order to increase the laser fluence at the surfaceof a work piece for micro-cutting with a high aspect ratio, a fiber with smaller core-diametershould be used.
    In this article, an advanced beam delivery system using a fiber which core size of down to 0.1mm and its applications are discussed. Deep UV power transmission from FHG-YAG laserthrough a highly OH-doped fiber is also discribed.
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  • Uichi KUBO
    1994 Volume 22 Issue 4 Pages 329-337
    Published: April 29, 1994
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Recently, laser and optical fiber techniques have been widely utilized in medicine. This paperdescribes the applications of their techniques in therapy, medical measurement and diagnosis. Laser beam guide system is an important problem in the medical laser instruments. In thebeam guiding system for clinical lasers, the required conditions are enough flexibility, smallersize and security to energetic power beam. A usual quartz optical fiber is a useful light beamguide. for near infrared and visible region. Infrared fibers (e. g. silver halide, chalcogenide) and hollow light guides are available for infrared light beams. OH-ion-doped quartz fiber andaluminum hollow light guide will be useful for ultraviolet light beams in the near future. Laserendoscopy, laser surgery, laser thermia, laser angioplasty and photodynamic therapy havebeen used clinically. Various diagnostic systems is based on laser-fiber sensors. Laser andoptical fiber techniques will have a great impact on the various medical fields.
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