Physical and Optical Properties of Poly(3-AlkylThiophene) with a View to the Fabrication of a Highly Nonlinear Waveguide

ABSTRACT

In order to take advantage of the very high nonlinear susceptibility of conjugated polymer materials, Poly(3- AlkylThiophene)s, P3AT, were synthesized in the laboratory. The physical, thermomechanical and linear optical properties of synthesized P3AT have been investigated and the first experimental attempts at creating nonlinear optical waveguides and determining their characteristics are presented. After synthesizing P3AT, the relationships between polymer chain characteristics and mechanical properties are investigated to see if the polymer is suitable for optical waveguide process technology. We also examine the optical attenuation of the synthesized material, a crucial factor in anticipating the relative opacity of the future component. For the first time we present the absorption spectrum of 3-Octylthiophene molecules in the Near Infra-Red (NIR) region that suggests optical losses for the material are about 0.6 dB.cm-1 at 1550 nm. Next we examined several waveguide structures such as ridge, buried and Strip Loaded WaveGuides (SLWG) based on P3AT material. For the buried waveguides, we have observed the signal transmission and in our opinion the low optical transmission of P3AT ridge and SLWG could be attributed to extrinsic losses (mainly scattering) due to both the remaining insoluble products in the polymer and to the poor adhesion between optical layers.

PCAS: 78.20.Ci, 78.30.Jw, 78.40.Me, 42.82.Cr, 42.70.Jk

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