Chirp Characteristics of Dual-Drive Mach-Zehnder Modulator with Finite DC Extinction Ratio

We present theoretical and experimental studies on the chirp of the dual-drive Mach-Zehnder (MZ) modulator with a finite DC extinction ratio. The chirp of the modulator was measured using the fiber response peak method and compared with the theoretically calculated values. The results show that the residual chirp of the MZ modulator could be substantially reduced by driving the modulator in a push-pull mode with unequal-amplitude signals