Measurement of the Nonlinear Refractive Index of PTS-polydiacetylene Channel Waveguides.

We have measured the nonlinear refractive index (n sub 2) of single-crystalline PTS-polydiacelylene channel waveguides at 1.06microns using two different techniques. The first method employs a Mach-Zehnder interferometer to determine the intensity- induced phase shift in the waveguide. In the second case n sub 2 is derived from the intensity-dependent birefringence, which is measured with a Babinet-Soleil compensator. With both measurements the value of n sub 2 in the direction of the PTS polymer chain axis is found to be ~3 x10 sup (-11) cm sup 2 /W. Such a large value of n sub 2 would allow all- optical device applications of this material at low power levels.