Research On All-fiber Polymer Electro-optic Modulators And Electrode System

ABSTRACT:Electro-optical modulators play an important role in high speed and broad-band optical communication systems and signal processing systems. The future growth of broadband communications will highly dependent upon the study of high bandwidth and low loss electro-optical modulators. How to improve the performance of electro-optic modulator has been one focus of the research. Since the1990s, the polymer electro-optic modulators have got people’s attention for their excellent performance.This paper studied a novel all-optical polymer electro-optic modulator, which made of CLD/APC. Differently from Mach-Zehnder structure modulator, the polymer film of this modulator is plated on Bragg grating. It completes the modulation by the shift of the resonant wavelength which is caused by the index change of the polymer. We have analyzed and designed the structure of the modulator. The main studies are summarized as follows:1. Learned the principle of the new electro-optical modulator, status quo of its development and the significance of the researches concerning it by reading a great number of literatures.2. We have analyzed the properties of the waveguide of the modulator; deduced the characteristic equation of the waveguide structure of the modulator. Using MATLAB, we analyzed the influence of the thickness of the cladding on the mode propagation. The results showed that the resonance wavelength of the grating will shift with the change of the refractive index of the polymer, when the thickness of the cladding between several microns.3. Designed the electrode system of the modulator. The Wheeler transformation method has been used to research the structure of the micro-strip electrode. In able to obtain a smaller conductor loss and better impedance match, the structure parameters of the electrode have been optimized, including the electrode width W, electrode thickness t, electrode gap between Au and ground.4. According to the structure, we analyzed the driving voltage and frequency response of the modulator. The theoretical calculations show:we can achieve significant modulation phenomenon when the voltage at8.2V. We also analyzed the effects of different frequency on the modulator.