Abstract: In order to solve the effective refractive index measurement problem of the ridged waveguide phase modulation, a three-port MZI(Mach-Zehnder Interferometer) structure is proposed. It can quantitatively measure and analyze the relative changes of the real and imaginary parts of the effective refractive index with the voltage varies of the PN ridged silicon optical waveguide and the polynomial fitting equation is derived. The experimental results are in good agreement with the fitting results, and then finally the characteristics of the ridged waveguide in the phase modulation process are obtained. This measurement method is simple and feasible, and can be used in silicon based optoelectronic integrated chips as a quantitative device for the detection of carrier modulation characteristics.

Key words: silicon-on-insulator waveguides, carrier dispersion, high-speed silicon photoelectric modulator, Mach-Zehnder modulator, phase modulation