DONG Yi,SONG Yan-fang,MA Lei,GAO Fang-fang.Surface morphology of refractive-index waveguide gratings fabricated in polymer films[J].Optoelectronics Letters,2016,12(5):329-332 Surface morphology of refractive-index waveguide gratings fabricated in polymer films Author Name Affiliation DONG Yi  School of Information and Electrical Engineering, Shandong Jianzhu University, Jinan 250101, China School of Mechanical and Electrical Engineering, Shandong Xiehe College, Jinan 250107, China  SONG Yan-fang  School of Mechanical and Electrical Engineering, Shandong Xiehe College, Jinan 250107, China  MA Lei  School of Mechanical and Electrical Engineering, Shandong Xiehe College, Jinan 250107, China  GAO Fang-fang  School of Mechanical and Electrical Engineering, Shandong Xiehe College, Jinan 250107, China  Abstract:       The characteristic modifications are reported on the surface of polymeric waveguide film in the process of volume-grating fabrication. The light from a mode-locked 76 MHz femtosecond laser with pulse duration of 200 fs and wavelength of 800 nm is focused normal to the surface of the sample. The surface morphology modifications are ascribed to a fact that surface swelling occurs during the process. Periodic micro-structure is inscribed with increasing incident power. The laser-induced swelling threshold on the grating, which is higher than that of two-photon initiated photo-polymerization (TPIP) (8 mW), is verified to be about 20 mW. It is feasible to enhance the surface smoothness of integrated optics devices for further encapsulation. The variation of modulation depth is studied for different values of incident power and scan spacing. Ablation accompanied with surface swelling appears when the power is higher. By optimizing the laser carving parameters, highly efficient grating devices can be fabricated. Hits: 4075 Download times: 0 View Full Text    Download reader