Extinction-ratio-independent method for total chirp measurement of integrated parallel Mach-Zehnder-modulators

A method is proposed for measuring total chirp of integrated parallel Mach-Zehnder-type modulators by analyzing optical spectrum components. It can be applied to characterize the integrated modulators with finite extinction ratio and permit to evaluate the chirp parameter at a specific frequency. An experiment measurement is then conducted to demonstrate the proposed method for an optical FSK modulator. The obtained result reveals the effectiveness of this chirp measurement method.