Based on signal spectral transforming principle, an all-optical return-to-zero (RZ) to non-return-tozero (NRZ) format conversion is realized by using a micro-ring resonator with the comb transmission spectrum and a narrow bandpass filter. Influences of devices′ parameters, such as different narrow bandpass filters, coupling conditions of micro-ring resonator and duty ratio of the RZ input signal, on eye-diagram quality of converted NRZ signal are investigated in detail. Results demonstrate that 2-order Butterworth filter is expected to decrease the influences of coupling conditions and the duty ratio of RZ signal on the conversion performances. In addition, by adjusting the ring-resonator size, the designed RZ-to-NRZ format converter is compatible with system having several bit rates signals. This will be better adapt to the development of future optical networks.<网络出版日期.2015-01-09