Perfluorocyclobutane-based polyester(arylene ether)s for applications in integrated optics

Novel ester-containing aryl trifluorovinyl ether monomers and the resulting perfluorocyclobutane aromatic ether polymers have been synthesized and characterized to exhibit desirable properties for low optical loss waveguide applications. The monomers were prepared via a very mild esterification between the intermediate 4-trifluorovinyloxybenzoic acid and diphenol/triphenol using N,N′-dicyclohexylcarbodiimide as the activating agent for carboxylic acid and 4-(dimethylamino)pyridinium 4-toluenesulfonate as the catalyst. Chloro and bromo atoms are incorporated into trifunctional trifluorovinyl aryl ether monomers to achieve good tunability in refractive index without introducing additional optical loss. Polymerization of the monomers proceeded in melt or solution to form perfluorocyclobutane-containing prepolymers with good processability. The combination of desirable optical polymer properties, such as thermal stability (T _g: 38-350°C), solvent resistance, tunable refractive index (n: 1.447-1.546 at 1310 nm), and low optical loss (as low as 0.26 dB/cm at 1310 nm) can be achieved through the copolymerization of highly fluorinated and flexible difunctional monomers with chloro/bromo-containing rigid trifunctional monomers.