DEMONSTRATION OF ALL-OPTICAL PHASE MODULATION IN POLYDIACETYLENE WAVE-GUIDES

We present the first demonstration of all-optical phase modulation in the waveguides of an organic material {poly[bis-(p-toluene sulfonate) of 2, 4-hexadiyne-1, 6-diol]}. The phase change as a function of optical intensity has been measured via the Mach-Zehnder interferometric method. A π phase shift has been observed for a 2-mm-long waveguide as the peak intensity is increased by ∼7 MW/cm2 for polarization parallel to the chain axis (λ=1.06 μm). Through detailed polarization-selective measurements we have established that the observed phase change is electronic (nonthermal) in origin. The results are highly encouraging in terms of all-optical device applications of the material.