Analysis Of The Properties Of Multi-cladding Waveguide In New Electro-optical Modulator

Inexpensive optoelectronic devices are needed to support the building of high-speed dense WDM optical fiber network and the realization of FTTH (Fiber-to-the-home). But the high price of optical modulator has seriously hampered the promotion of optical communications and applications. Therefore, it is necessary to develop a kind of high-speed electro-optical modulator with low cost but good performance so as to meet the current need of route network and the future need of the FTTH.The paper mainly studied the basic properties of multi-cladding waveguide which is an important part of a new high-speed electro-optical modulator. The main studies and innovations 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; studied the status quo of the application of multi-cladding waveguide and the specific methods of analysis.2. Deeply analyzed the properties of multi-cladding waveguide which is an important part of the new modulator; deduced the characteristic equation of four-cladding waveguide structure in the modulator; ascertained the best range for the thickness of the first clad, ITO electrode and polymer coating by analyzing the transmission constant and the mode field distribution of multi-cladding; analyzed the dispersion characteristics of the multi-cladding waveguide and obtained the corresponding dispersion curve.3. Analyzed the relationship between refractive index of polymer, modulation voltages and the changes of refractive index after FBG and modulation voltage are added to the multi-cladding waveguide containing ITO and polymer and obtained the changing rule of FBG resonant wavelength; analyzed the impact of modulation voltage's magnitude on the resonant wavelength of FBG and calculated the minimum modulation voltage that can meet the condition of the Extinction Ratio, which provides theoretical foundation for the development of the new modulator based on FBG multi-cladding structure.4. Carried out some experiments concerning multi-cladding waveguide and set up the experiment program of obtaining the first cladding of the desired multi-cladding waveguide through fiber axial-side rubbing; obtained the changing rule of resonant wavelength of the FBG added into the core of multi-cladding waveguide and the changing rule of its related properties, which provides the experimental basis for the development of the new modulator based on FBG multi-cladding structure.