Modification Of PMMA Poled-Polymer Film And Its Application For Optical Waveguide

There were advantages, for nonlinear optical (NLO) poled polymer materials, of large nonlinear optical coefficient, low permittivity, easy processing and monolithic integration. It was thus expected that they played an important role in the field of integrated optics, especially high performance photonic devices, such as high-speed optical switches, tunable filters and broadband optical modulators. In recent years, organic-inorganic hybrid materials have drawn much attention, as involve the advantages of both organic and inorganic phases such as high transmitance, great flexibility and better stability and toughness.In this thesis, two kinds of NLO polymer thin films including ploymer/chromophore guest-host, organic-inorganic hybrid/chromophore were successfully prepared by dip-coating technique, and a Y-type optical waveguide was obtained using hybrid film as core layer with photo-bleaching technique.Azo-dye polymer films of the guest-host system were prepared with disperse red-1 (DR1) as NLO active chromphore and poly (methylm ethacrylate) (PMMA) as polymer matrix. The T_g of poled polymer with 10wt% DR1 (PR-10) was 94℃, while that of PMMA was 105℃. The poling condition was optimized and the optimal orientation order parameter (Φ) of PR-10 was estimated to be 0.182. After 30d at room temperature, theΦvalue of the poled films decreased into about 70%, showing bad relaxation-resistance. NLO coefficient (d₃₃) of 1.90×10^-8esu was reached for the film after corona poling by the SHG measurement.Using the MMA as organic component, TEOS as inorganic component, MSMA as coupling agent, the organic-inorganic hybrid PMMA/SiO₂ was also synthesized successfully via sol-gel route. Hydrid films of PMMA/SiO₂/DR1 were developed. The T_g of hybrid sample PCR-0.6 with n(TEOS)/[n(MMA)+n(MSMA)]=0.6 was 165℃, much higher than that of PR-10. The hybrid films showed excellent stability of chromophore molecules ordered as theΦwas able to be maintained about 91% of its initial value at room temperature for 60d.Meanwhile, a Y-type optical waveguide was obtained using PMMA/SiO₂/DR1 as the core layer and PMMA/SiO₂ as the substrate with photo-bleaching technique, and the preparation parameter was optimized in details, especially the fabricaiton of Al-mask and its effect on properties of films with photo-bleaching. The optical properties of the Y-type optical waveguide were testd with the coupling optical fiber, in which the optical power ratio was 44:56 for two branches and the optical loss was around 9dB with a powermeter.