Preparation and properties of novel silicone-based flexible optical waveguide

Abstract

UV curable novel silicone polymers, Nano-Hybrid Silicone (NHS), having high thermal stability, low-shrinkage and high transparency were developed. The optical waveguide could be fabricated by direct UV exposed patterning method, since photolithograph using NHS could be available. Two kinds of NHS for optical waveguide were developed, one is for optical waveguide on Si substrate and the other is for film optical waveguide. The optical losses of these waveguides measured by cut-back method at 850 nm were significantly low, and indicated 0.05 dB/cm (Si substrate waveguide) and less than 0.1 dB/cm (film waveguide) respectively. Heat durable tests of these waveguides were carried out for surface packaging technologies under lead free solder melting temperature, and no significant changes of optical loss were observed. Especially with the waveguide on Si substrate, the optical loss increase was less than 0.02 dB/cm without changing of shape after the heat resistance test at 270 degrees Celsius for 10 minutes. UV durable tests of these waveguide were also carried out for the adhesion using UV curable resin on electric board. No change was observed with optical waveguide capability after UV exposure (10 J/cm2 at 365 nm). Furthermore, value movement of optical loss was small at preliminary tests of heat-cycling and reliability under the high temperature and humidity condition according to Telcordia specification. Due to their various processes durability, the waveguides made with novel silicone-based material are expected to be suitable for practical uses.