Browsing by Author "SAKTIOTO"

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    PEMODELAN DENSITAS PLASMA HIDROGEN PADA KESETIMBANGAN TERMODINAMIK TEKANAN ATMOSFER
    (2013-05-24) YOHANES, HENDRA; SAKTIOTO; DEFRIANTO
    The equilibrium densities of hydrogen species have been determined by a computational modeling. The thermodynamic equilibrium process is required to expose plasma on a sample at a stable and controlled condition. Hydrogen species densities have been modeled based on the time-dependent continuity equation and a modified Arrhenius equation. These equations are used to integrate the density change over the time. This simulation is designed to find the equilibrium hydrogen species densities and reaction rates, both among the thermal hydrogen species and among the non-thermal hydrogen species, at a constant atmospheric pressure and low temperature. For the thermal hydrogen plasma, the equilibrium density of electron, H2, H, H2+, H+, and H- are obtained from the numerical calculation is 2.6×1010; 5.12×1024; 9.23×1022; 4.07×1021; 3.58×1022; and 5.12×1020 m-3, respectively. And, for the non-thermal hydrogen plasma, the equilibrium density of electron, H2, H, H2+, and H+ are acquired from the numerical simulation is 4.03×1023; 1.01 × 1025; 6.05 × 1024; 3.02 × 1024; and 3.36 × 1023 m-3, respectively. From the reaction rate gained, it can be inferred that the dominant process of electron in thermal hydrogen is the recombination, where its density decreases in order to reach the equilibrium. Meanwhile, the dominant process for electron in non- thermal hydrogen is the ionization, where its density increases in order to reach the equilibrium. From this modeling, the relationship between equilibrium electron densities in hydrogen plasmas and the required time to reach equilibrium was found.
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    POWER PROPAGATION ON LINEAR MXN FIBER COUPLERS USING MATRIX TRANSFER
    (2014-05-22) SAKTIOTO
    Coupling power propagation on MXN monolithic fiber coupler has been calculated by using matrix transfer based on coupled-mode theory. Launching input power to one fiber on linear 1X7 monolithic fiber coupler shows that power is distributed to the other fibers with different coupling velocity. It is found that the outer fiber has the slowest coupling velocity and high transferred power. The measurement of output power of 1X7 fiber coupler as fiber combiner has been theoretically and experimentally done. The experimental result is compared to the theoretical model. A small different peak at certain distance occurs due to the coupling velocity. This MXN multi fiber coupler is applied for various optical power circuits