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Nonresonant n2 and TPA coefficient measurement in polymer waveguides by different measurement techniques



Journal of the European Optical Society. Part A, Pure and applied optics 7 (1998), No.2, pp.159-168
ISSN: 0963-9659
Journal Article
Fraunhofer IOF ()
nonresonant chi(3) nonlinearity; polymer; two photon absorption; waveguide

Nonlinear optical waveguide elements have to be operated at wavelengths where the waveguide material exhibits minimum linear alpha and higher-order alpha2 is as large as possible. The dispersion of these two quantities has been measured in the wavelength range between 780 and 990 nm. A stable semiintegrated Mach-Zehnder interferometer as well as a spectral broadening set-up were used. The light source was a Ar-pumped tunable Ti:sapphire laser, generating picosecond light pulses. The measurement have been performed on one class of conjugated polymers, substituted poly(phenylenevinylene) (PPV), which are promising candidates for the demonstration of nonlinear switching in waveguide elements. Low-loss waveguides (< 1 dB cm-1) with extreme stability against pulsed optical intensity (up to 16 GW cm-1), allowing for a nonlinear induced phase shift of more than 3 pi have been demonstrated. The nonresonant n2 values are several times 10(exp-14) cm2 W-1 for the two PPV derivates measured. Spati al solutions have been observed the first time in a polymer waveguide.