The implications of sidewall roughness depth and waveguide dimensions on optical splitter device performance

Optical waveguide has several special features such as compactness, relaxed large bandwidth, fabrication tolerance and low fabrication cost. However, the inaccurate fabrication leads to non-uniformity in waveguide surface and eventually causing impact to optical output power. In this study, the effect of waveguide non-uniformity on power distribution 1x2 optical splitter was studied. Data is collected regarding the effect of sidewall roughness (SWR) on both sides, upper side and lower side of S-bend optical waveguide. Furthermore, graphs are being generated from the data simulation such as total optical output power, average optical output power and power distribution. The optical power output on the path with side wall roughness was less than the optical power output on the path without side wall roughness and the effect is different according to the location of SWR. Hence, propagation loss in transmission is mainly due to the side wall roughness parameters were analysed where light that propagates through the waveguide was scattered by the roughness. Besides, when the roughness depth of the side wall roughness increases, the optical power output loss will also increase as well as the splitting ratio variation. Finally, we introduced the simple method to determine the quality of fabricated waveguide through the analysis of sidewall roughness parameters