Nonlinear optical polymer applicable for all-optical wavelength converters in communications bands near 1.5 μm

We prepared acrylic nonlinear optical (NLO) polymers that contained a chromophore with a π-conjugated imine bridge between phenyl and benzothiazole groups, 2-(methyl-{4-[(6-nitro-benzenothiazol-2-ylimino)-methyl]-phenyl}-amino)-ethanol, for all-optical wavelength converters in optical fiber communication. The glass transition temperature (Tg) of the copolymers is between 130 and 143 °C. The molecular weights of the copolymers are comparatively high for obtaining films. An NLO polymer film containing ca. 30 mol% of chromophore shows a high second-order nonlinear optical coefficient (d33) at 1.55 μm, 35 pm/V, as well as a low optical loss at about 0.775 μm, 3.9 dB/cm. The aligned dipole orientation in the film is comparatively thermostable. The deformation difference between the centers of the poled and unpoled regions after periodic poling for quasi-phase matching (QPM) is small, which lessens the light scattering loss.