Organic–inorganic hybrid materials for flexible optical waveguide applications

Abstract

Novel organic–inorganic hybrid materials of 3-acryloxypropyl trimethoxysilane and 4,4′-(hexafluoroisopropylidene)diphenol were synthesized by non-hydrolytic sol–gel processing. Thick, crack-free films were produced by spin-coating without high volume shrinkage during further treatment of the films. The optical properties of the materials were precisely tailored by adjusting the chemical composition of the materials. The tunability of the refractive index allowed us to fabricate step-index optical waveguide structures with well-defined and reproducible refractive index differences to within 0.001. The relatively large, negative thermo–optic coefficients (dn/dT, °C) were obtained in the temperature range below 100 °C and displayed a systematic decrease with the addition of the organic compounds. Using these hybrid materials, we fabricated a flexible optical waveguide based on a soft-lithography technique. The bending loss of a flexible waveguide array was measured and found to yield no significant loss above 2 mm diameter curvature. The transmission performance of each waveguide channel was tested using a 10 Gbps data stream. The electrical output signal from a photodetector, connected to a wide-band oscilloscope, displays a clear 10 Gbps eye pattern.