We report on the linear and nonlinear-optical properties of 4-dimethylamino-4Ј-nitrostilbene (DANS), 4-diethylamino-1-nitrobenzyl (DANB), and 4-͓N-ethyl-N-(2-hydroxyethyl)͔amino-4Ј-nitroazobenzene) (Disperse Red 1;DR1) side chain polymers whose second-harmonic generation at the telecommunication wavelength of 1.55 m was investigated. Measured ultraviolet-visible-near-infrared spectra were analyzed with an inhomogeneously broadened line-shape model, in particular, in the long-wavelength tail of the electronic transitions, which determines the absorption loss at the second-harmonic wavelength. The nonlinear-optical coefficients were measured at different poling temperatures and poling fields by the Maker fringe technique. On the basis of the measured material parameters we calculated the normalized conversion efficiencies for guided-wave second-harmonic generation at 1.55 m. The DR1 polymer exhibited the best nonlinearityabsorption trade-off, with a calculated normalized conversion efficiency of several hundred percent per watt, whereas the figures of merit for DANS and DANB are lower and comparable with each other.

Second-harmonic generation using modal dispersion phase matching has been demonstrated in reactive-ion etched waveguides based on the organic nonlinear polymer poly (methyl methacrylate)-Disperse Red 1 [N′ ethyl N-ethanol-4-(nitrophenylazo)phenylamino]. The measured propagation losses were 6 dB/cm at the fundamental and 10 dB/cm at the second-harmonic wavelength, dramatically less than we obtained previously for the harmonic in photobleached waveguides. A figure of merit of η=0.1%/W for second-harmonic generation was obtained with a modest nonlinearity of 3 pm/V at 1607 nm in a 2 mm long waveguide.

Modal Dispersion Phase Matching appears to be currently much better adapted to parametric mixing in polymeric material waveguides than Quasi Phase Matching. For second harmonic generation at telecommunication wavelengths, using organic materials should allow better performance than with ferroelectric crystals. Promising results are expected in view of theoretical expectations and continuously improving experimental past and current results.

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