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

摘要

We prepared acrylic nonlinear optical (NLO) polymers that contained a chromophore with a pi-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 (T_g) of the copolymers is between 130 and 143 deg C. The molecular weights of the copolymers are comparatively high for obtaining films. An NLO polymer film containing ca. 30 mol percent of chromophore shows a high second-order nonlinear optical coefficient (d_(33)) at 1.55 mu m, 35 pm/V, as well as a low optical loss at about 0.775 mu m, 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.