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Author: search.filters.author.Fadhali, M.Subject: search.filters.subject.Coupling coefficient

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    Development of single mode fiber coupling coefficient using kinetic model
    (2010-12-01)
    Phattaraworamet, T.
    ;
    Saktioto, T.
    ;
    Ali, J.
    ;
    Fadhali, M.
    ;
    Yupapin, P. P.
    We propose a simple kinetic model that can be used to improve the coupling coefficient value of a single mode fiber coupler in the fabrication process. The proposed model is time independent, where the internal and external parametric functions are included. The simulation is integrated over the coupling ratio range for the various fiber separations. The coupling coefficient value of the device is examined by using the coupling ratio range from 1% to 75%. The result obtained is compared with the experimental results, where it is noted that the separation of fiber cores significantly affects the coupling coefficient, exhibiting exponential behavior. We also found that the coupling coefficient gradient is significantly changed with respect to the coupling ratio. This model can be used to determine power losses of the fiber coupler at the coupled region, while the fabrication of the fiber coupler is operated. © 2009 Elsevier GmbH.
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    Tunable coupling ratio for optical switch application
    (2010-12-01)
    Saktioto
    ;
    Hanim, Nor Faridah
    ;
    Fadhali, M.
    ;
    Yupapin, Preecha
    ;
    Ali, Jalil
    This paper describes the breakdown voltage of SiO<inf>2</inf> fiber using Pockel's effect and empirical equation. The model is evaluated by coupling coefficient and refractive index changes. A 1×2 single-mode directional coupler switch has been fabricated. A large electro-optic effect causes a change in the optical properties when a slowly varying electric field is applied. A model to describe the breakdown voltage for driving the optical switch of the fusion SiO<inf>2</inf> fiber coupler has been developed. A voltage is applied through sectioned electrodes along the coupling length. This model uses the coupling coefficient and the changes in the refractive index to describe the optical switching. The change of refractive index due to the linear electro-optic Pockel effect and an empirical equation are used to calculate the value of coupling coefficient. The result shows that the changes of the refractive index increases exponentially as a function of separation fiber axis from 5 to 8 μm. The breakdown voltage and refractive indices difference depict a linear relationship. The increment of coupling coefficient shows that the value of voltage is reduced. © 2010 SPIE.
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    Characterization of coupling power for single-mode fiber fusion
    (2010-10-01)
    Saktioto, T.
    ;
    Ali, J.
    ;
    Yupapin, P. P.
    ;
    Fadhali, M.
    Fabrication of single-mode fiber coupler by heating fibers on a flame is very common and popular. However, controlling the input and the output power quantities of the fiber coupling process is neither easy nor similar. Power losses occur at the coupling length as the effect of the geometry and structure of fibers during and after fusion. In application, the power losses will affect sensor devices, e.g. optical switch. This paper proposes power splitting into the second fiber junction as a new model by deriving and integrating the coupling power with two conditions of refractive index changes. First is the change in the vertical part and second is the change in the vertical and the horizontal parts. Both conditions are studied by perpendicular and parallel directions of coupling power. The model is examined with a linear change of refractive index where power absorption and reflection are accumulated by power losses. The result shows that power increases as the effect of losses by simulation. These power losses are lost by radiation out of cladding and fiber heating. © 2009 Elsevier GmbH.