Study on the Performance of Y-Branch Waveguide Modulator Affected by the Fabrication

The performance of Y-branch waveguide (YBW) modulator which is affected by the fabrication has been researched. The range of Y-branch corner deviation is obtained by analyzing the structural loss of the branch in the YBW which is limited by fabrication resolution. The effects on splitting ratio, mode field and coupling loss of YBW are also discussed through changing the waveguide width. It can be obtained that the difference between the two widths should be less than 0.25μm to meet the requirement of 5% error. And the maximum coupling efficiency can be achieved by adjusting the fabrication of waveguide to change the waveguide mode field. The corresponding fabrication tolerance can be attained based on the analysis.