Measurement of nonlinear refractive index and transmission in polydiacetylene waveguides at 1.319 μm

Nonlinear optical measurements in strip-loaded channel waveguides of poly(4-BCMU) at 1.319 μm are reported. Using a pulse-modulated interferometry method, the intensity-dependent refractive index is found to have an electronic contribution, n2=(4.8±2.7)×10−8 cm2/MW, and an estimated thermal contribution, n2=−(7.9±4.5)×10−11 cm2/MW, for 60 pS laser pulses at 76 MHz. The two-photon absorption coefficient β is less than 0.25 cm/GW. Figures-of-merit suggest that poly(4-BCMU) has properties desirable for all-optical devices, but that fabrication losses and thermal effects due to absorption will limit device performance.