Transversely tapered hybrid electro-optic polymer/sol-gel Mach–Zehnder waveguide modulators

We show results of a proposed hybrid modulator structure that reduces both the optical loss and half wave voltage (Vπ). A sol-gel waveguide core transversely sandwiched between two Mach–Zehnder arms of electro-optic (EO) polymer cores enables an adiabatic transverse transition between the sol-gel and the EO polymer cores without the need for Y branches. The undercladding thickness is reduced to 3.7μm with negligible further optical loss from the bottom electrode. EO modulation with Vπ of 1.8V at 1550nm is demonstrated using a guest-host EO polymer, with an optical insertion loss of 13.7dB in the transverse magnetic mode.