Polymeric electro-optic Mach-Zehnder modulators with truncated Y-junctions

We propose and demonstrate a Mach-Zehnder type electrooptic (EO) modulator with truncated structure of the Y-junctions. The length of the branching zone is reduced to ~3 times in the proposed structure compared with the normal Y-branch structure. The symmetric and asymmetric structures of the junction are studied to consider the fabrication tolerance. We used the simple laser writing process to fabricate the device. The reliabilities of the EO polymer modulators made from the common side-chain polymers were investigated and found guide loss of 0.9 dB/cm in TE mode. The device was hermetically sealed in an inert gas and then found the reduction of V_pi at room temperature was ~7% over 5 weeks operation with 30 mW input power. However, V_pi increases to ~18% when the sample was heated to 50deg;C. The simulated results show the reduction of device length significantly by choice of higher electrooptic coefficient core materials