Low V-pi electrooptic modulators from CLD-1: Chromophore design and synthesis, material processing, and characterization

A ring-locked, phenyltetraene-based, second-order nonlinear optical chromop hore (CLD-1) was synthesized. It shows no drop in decomposition temperature compared to its phenyltriene analogue, while the molecular nonlinearity in creases by a factor of 2.25 from 6252 x 10(-48) to 14065 x 10(-48) esu at 1 .9 mum. Thin films and waveguide devices were prepared from CLD-1/PMMA and CLD-1/APC an amorphous polycarbonate) composites to study its electrooptic (EO) activity, optical loss, and photostability. An average EO coefficient of 92 pm/V at 1.06 mum was achieved in a 25 wt % CLD-1/APC composite. Mach- Zender (MZ) modulators fabricated from CLD-1/APC showed good thermal stabil ity, low optical loss, low modulation voltage, and high extinction ratio. T he photochemical stability of the CLD-1/APC modulator can be dramatically i mproved by operating in an inert gas atmosphere. Evidence shows that the pr edominant photochemical degradation mechanism of the material in air at 1.5 5 mum is the reaction between oxygen and photoexcited polyene-based chromop hores.