Low-loss polymer optical waveguides using fluorinated poly(arylene ether sulfides and sulfones)

We synthesized novel cross-linkable fluorinated co-poly(arylene ether sulfide)s and co-poly(arylene ether sulfone)s for optical waveguide applications, having high thermal stability, high optical transparency in the infrared communication region, and small birefringence. The refractive index of the materials can be easily controlled in the range of 1.50∼1.58 by changing the copolymer composition in the materials. The birefringence of the polymer films was 0.0015∼0.0039 at the wavelength of 1.55 μm. These are much lower than those of fluorinated polyimides for optical waveguides. The optical loss after storing at 300°C for 1 h remains almost constant, demonstrating the thermal stability. The propagation losses of the fluorinated polymers were 0.1∼0.3 dB/cm and 0.2∼0.5 dB/cm at the wavelength of 1.3 and 1.55 μm, respectively. These excellent optical properties have allowed us to fabricate a variety of optical devices such as straight channel waveguides, directional coupler, and polymeric wavelength filter.