Florinated polyimide for low-loss optical waveguides at 1.55μ m

Abstract

Fluorinated polyimide (FPI) is an attractive material for fabricating low-loss optical waveguides at 1.55 micrometers , because of its superior optical and thermal properties. Although FPI planar lightwave circuits (PLCs) are usually fabricated on silicon substrate, such PLCs exhibit relatively high polarization dependence and high transmission loss compared with those of silica PLCs. Use of an FPI substrate overcomes these problems that mainly originate from the difference in thermal expansion coefficient between FPI and silicon. It improves the optical property of FPI waveguides, e.g., the transmission loss and polarization dependent loss for straight waveguides reduce to less than 0.3 dB/cm and 0.1 dB, respectively, in the 1.55-micrometers band. The use of FPI substrates will enable the fabrication of high-optical-quality FPI PLCs such as 1x8 splitters.