Second order nonlinearity of a radio frequency sputtered Corning7059 glass film waveguides was exhibited by corona poling. Phase-matched blue second harmonic generation was clearly observed with a fundamental light source of Ti: Sapphire laser operating at 860nm. The phenomenological mechanism responsible for the induced second order nonlinearity was proposed from the experimental results. The nonlinearity of glass films, which was examined by a time dependent decay of quadratic nonlinear coefficients (d coefficients), was influenced by changing the glass composition. Glass composition of SiO₂-BaO-B₂O₃ and/or SiO₂-BaO-Al₂O₃ was found to have effective roles to induce larger nonlinearity and to maintain the induced nonlinearity for a long period of time. Isothermal decays of the d coefficient in corona-poled Corning 7059 glass films were also investigated and the activation energy was obtained to be 0.5eV.

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Laser-dye doped plastic optical fiber amplifier (POFA) is fabricated and its basic performances are demonstrated. As doped dye, Rhodamine B (RB) is prepared. Output power of 1kW with a gain of 30dB can be obtained by using a RB doped POFA at a concentration of 1 ppm. The energy conversion efficiency, which is defined as output signal power normalized by launched pump power, is 25%. Possibility of plastic optical fiber laser (POFL) is discussed by analyzing a rate equation of laser. It is proved that a RB doped POFL (core diameter : 100μm, length : 30mm) has high performance around 580nm. As one of the applications of POFA, photodynamic diagnosis (PDD) for medicine is proposed. Fluorescence from Zinc-Porphyrin is confirmed by a Rhodamine 6G doped POFA.

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The investigations on dc tracking resistance should be enhanced due to the increasing of organic insulating materials being used with do power. This paper describes the do tracking failure of organic insulating materials by use of the IEC Publ. 112 method. Although the use of direct voltage is spreading in our society currently, there have been few studies on the mechanism of the tracking resistance with direct voltage. This paper presents a study on tracking resistance of paper base phenolic laminates (PL) and glass cloth base epoxy resin laminates with and without flame-retardant (EX1, EX2) with direct voltage application. The test with alternating voltage is also made in order to compare the influence of discharge wave forms on tracking failure for that with direct voltage application. The test results show that the apparent CTI values with direct voltage are bigger than those with alternating voltages. It can be considered that this difference is caused by the discharging characteristics which depend on the types of voltage wave forms.

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[in Japanese]

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