| The main focus of the current research has been to improve the performance of the waveguide based Electro-optic (EO) photonic devices, namely, Mach-Zehnder interferometers. These devices were poled in a Push-Pull configuration in a DC biased fashion to reduce the drive voltage (Vpi) and also to carry out the real time study of the EO activity. Under such a DC condition, sub one volt value of Vpi has been achieved at optimum poling conditions, which afforded the second lowest value of Vpi ever observed for waveguide EO devices available in the literature. Using the statistical model for the chromophore order parameter, the third order contribution under the optimum poling condition was calculated and was found to be negligible in comparison with the EO effect.; To improve the thermal stability and the optical loss, novel hybrid Mach-Zehnder devices were fabricated using sol-gel composites synthesized by modified procedures. The bottommost thicker layer of sol-gel enabled the smooth transition of the coupled light into the EO layer and light propagation was nearly adiabatic with the total device loss less than 5 dB for a 3 cm device. Although these devices showed 12.8 V of Vpi, it can be further reduced by using a better EO polymeric system having higher EO coefficient.; Attenuated Total Reflection (ATR) was set up to measure EO coefficients in thin films. Besides the ease of sample preparation and measurement, ATR enabled the measurements of EO coefficients independently and it could assess the piezoelectric contribution which was shown to be less than 3% in comparison with EO effect.; Novel chromophores containing indole as a bridge unit and different acceptors were synthesized successfully and the experimental hyperpolarizabilities were compared with those of computational results using DFT which showed promising hyperpolarizability values in comparison with the standard chromophroe EZ-FTC. However the break in the conjugation between aniline donor and acceptor through an indole unit probably caused the lower experimental hyperpolarizability, as measured by HRS technique. Better functionals than PBE, such as B3LYP though expensive, was found to be needed for geometry optimization in these calculations, which gave more reliable results. |
