A schematic view of the device optical power splitter designed by Opti BPM designer version 10.0/2010 used for this study is shown in Fig. 2. Principally, the waveguide is designed to have length of with core (AESO) and cladding refractive indices of and , respectively. The latter is modified, as will be discussed later, to obtain a relatively high output power. In addition, the wavelength used was 1.55 um, which is the most promising wavelength for optical communications because of minimal attenuation in the optical fiber. Initially, the branching angles of the two output arms, and , are assumed to be not equal to an arbitrary value. Thus, an output power dividing ratio is expected to be achieved. Generally, as previously mentioned, the branching angle should be fixed at a small value to decrease the excess loss resulting from the effective uptapering of the branches and to ensure that the optical splitter is adiabatic (i.e., the local super mode does not couple to higher-ordermodes). The width of the waveguide (w), assuming a 10 um single mode operation, was then changed to investigate its influence on the output power.