Power modulation in axial and lateral fiber displacements in a fiber-to-fiber design

In this study power transmission modulation for different fibers in a fiber-to-fiber design using two different light sources is reported. A fiber-to-fiber arrangement is used in which the source light is directly coupled to the first fiber and the second fiber delivers the light to a power meter. Arrangements with three sets of different type fibers are tested in this study and output powers are monitored with the white lamp or red LED as illumination light sources. Using this arrangement the variations of the power as a result of axial (Z-direction) and lateral (X- and Y-direction) displacements of the second fiber are monitored. Theoretical models are also used to evaluate the power transmissions for the related geometries and comparison is made with the experimental results. Our results in general agree with the theoretical predictions and the small deviation is because of the fact that those theoretical formulas are more precise for the case of small core fibers for small axial and lateral displacements while we are using large core fibers and relatively long displacements. The agreement with the theoretical results for the assumed numerical apertures is good for the small axial distances but a difference is noted for the larger axial separations. The results of this experiment verify that the core diameter, fiber material, and other fiber parameters affect the power transmission and such parameters can be investigated experimentally using the reported fiber-to-fiber arrangement.