Optimization of the Mach-Zehnder modulator using polymer asymmetric rib waveguide

In order to shorten the branch length of Mach-Zehnder modulator, the asymmetric rib waveguide was researched in Mach-Zehnder electro-optic polymer modulator. Full vector finite difference beam propagation method was applied to analyze systematically their transmission loss with different parameters. The structure was optimized by choosing optimal design solution such as the rib width w=4μm, the branch height g=11μm, the outer slab width of core layer in bending waveguide s=2μm and the length of the sine-bending waveguide L1=350μm. The results show that if symmetric rib waveguide is replaced by asymmetric rib waveguide, the length of branch waveguide could be reduced by 30% under the same conditions of transmission loss. The results will have a certain reference value to the design of polymer optical waveguide in M-Z modulator.