Investigation Of Electro-Optic Modulating Based On Double Metal-Cladding Polymer Waveguide

In the field of optoelectronics, the linear electro-optic effect of polymer is the focus of investigation. By comparison, the quadratic electro-optic effect (QEO) of polymer has not been given appropriate attention yet. The measurement of QEO coefficient in organic polymer is fundamental for the fabrication of QEO devices. Traditional measurements such as cross-polarizer method based on the phase retardation and Kramers-Kronig calculation based on the sample absorbance spectrum can not give all the elements of QEO coefficient tensor. In this thesis, based on attenuated total reflection technique, not only the all the elements of the QEO coefficient tensor of the organic polymer but also the DC Kerr Coefficient was obtained by employing a simple sample, the fabrication of which is very easy.A double metal-cladding polymer electro-optic modulator based on free-space coupling technique is also given in this thesis. Free-space coupling technique, which expands the range of effective refractive index, makes it possible to obtain the high order guided modes excited in small incident angles. High order guided mode in double metal-cladding waveguide is more sensitive to the refractive index variation of the polymer guiding layer by comparing with low order guided mode. This character makes the demonstrated modulator possessing a low driving voltage in consistent with a high modulating depth. Because of the employment of free-space coupling technique, this modulator has the merits of high sensitivity, simple structure, small volume and easy integration by comparing with modulators based on prism coupling.