Spectral Modulation Of Ultra-Wideband Femtosecond Laser Pulses And High Speed Electro-Optic Modulator

Successful amplification of the ultrashort laser pulses is limited primarily by the gain narrowing effect which has resulted in rapid progress in spectral modulation techniques. Fortunately, the bandwidth of the femtosecond Surface Plasmon Polariton (SPP) pulses which have attracted much attention due to high packing densities and strong nonlinearities, is broad enough to fulfill the spectral modulation of the Ultra-WideBand (UWB) femtosecond laser pulses. In this dissertation, employing the SPP pulses launched by a Kretschmann configuration, whose reflectivity curve has the characteristic of the ultra-broad bandwidth, we observe a frequency-dependent loss with greater attenuation at the peak of the spectrum profile than in the wings both in theory and experiment, which is very useful for adequate spectral modulation. We can implement the arbitrary spectral modulation of the UWB femtosecond laser pulses, by designing the appropriate thickness of the gold film which determines the bandwidth and the attenuation depth of the SPP and adjusting the angle of incidence which can control the central wavelength.Also, in this dissertation, a new LiTaO3 Electro-Optical (EO) Modulator expected for 26 GHz employing the spontaneous Polarization Reversal Technology is studied, which provides opportunities to meet the increasing bandwidth demand of next generation communication networks. Firstly, analyze the propagation characteristics in Ni-diffused LiTaO3 channel waveguide using effective index method and Marcatili's method; then, study on the Coplanar Strips (CPS) employing the Conformal Mapping and the important parameter: Overlap Integral FactorΓ; at last, measure the EO coefficient using the new EO modulator and achieve a larger modulation index employing the spontaneous Polarization Reversal Technology.