Hybrid electro-optic polymer/sol-gel waveguide modulators fabricated by all-wet etching process, using straight channel and Mach-Zehnder waveguides

Abstract

ABSTRACT We report hybrid electro-optic (EO) polymer/sol-gel waveguide modulators with a structure for an EO polymer confined laterally in a sol-gel over cladding, which is fabricated by all-wet etching process. The structure enables an adiabatic transition between the sol-gel waveguide and thick EO polymer overlayer. Intensity mode is confined well in 0.9- µ m-thick EO polymer overlayer, which reduces a half wave voltage (V ) due to increased overlap integral in the hybrid EO modulator. Straight channel birefringence EO modulators with the structure reduce the V by the factor of 4 after guided wave well confined in the EO polymer. The straight channel waveguide modulator with 2.4-cm-long electrode demonstrated the V of 13 V. Preliminary testing results using a Mach-Zehnder waveguide modulator were investigated to reduce the V further. Keywords: Electro-optic polymer, sol-gel waveguide, fiber-coupling loss, wet etching, hybrid modulators 1. INTRODUCATION Polymeric waveguide electro-optic (EO) modulators have a great potential to realize high-speed optical communication. Compared to inorganic modulators, polymeric EO modulators have large bandwidth