Hybrid electro optic modulators with subvolt drive voltages

Hybrid organic-solgel nonlinear materials are being investigated as high speed low voltage modulators. This paper provides a summary of our recent results in this area. Various design structures will be reviewed. We have also demonstrated near ∼100% poling efficiency in several generations of hybrid electro-optic (EO) polymer/sol-gel waveguide modulators, using crosslinkable and guest-host EO polymers. In these devices, the EO polymer was poled using an electrically conductive sol-gel cladding in the hybrid modulator, such that the poling voltage was completely applied to the EO polymer layer. Stable long-term operation is preferred for industrial applications. The hybrid polymeric modulator has the additional benefits of stable and low loss optical coupling to standard optical fiber, and stable waveguiding, since the thermally and optically stable sol-gel core in the passive regions plays the primary role in optical coupling. Fine refractive index control of the EO polymer is not required in the hybrid modulator, which is another advantage for long-term stability. In the hybrid approach, whenever the EO polymer core has higher refractive index (e.g. 1.63-1.68) than the sol-gel core (1.50), coupled and waveguided light in the sol-gel core can be adiabatically transferred to the EO polymer core and back through vertical tapers in the sol-gel. We will review our recent results including demonstration of a V_π of 0.65V at 1550nm.