Low half-wave voltage and high electro-optic effect in hybrid polymer/sol-gel waveguide modulators

Abstract

The authors report on hybrid electro-optic (EO) polymer–sol-gel modulators with low half-wave voltage $\left(V_{\pi }\right)$ and low insertion loss. Larger EO coefficient $r_{33}$ results from the high poling field achieved when EO polymer is sandwiched between sol-gel cladding layers. The reduced interelectrode distance $\left(d\right)$ resulting from the elimination of the sol-gel core layer in the active region further reduces $V_{\pi }$ . Straight channel phase modulators operate with $V_{\pi }=4.2\mathrm{V}$ at $1550\mathrm{nm}$ using a reduced $d$ of $11.5\mu \mathrm{m}$ , which corresponds to an $r_{33}$ of $78\mathrm{pm}∕\mathrm{V}$ , among the highest $r_{33}$ reported. The authors also examine a Mach-Zehnder modulator with $V_{\pi }=3.9\mathrm{V}$ using a conventional $d$ of $15\mu \mathrm{m}$ .