Engineered transfer function InP Mach-Zehnder modulator for bandwidth enhancement and nyquist shaping

A segmented modulator which shapes the optical spectrum of the modulated signal by resonating sections is presented. The modulator enhances the bandwidth of the slow driving electronics at its input. 1.5-fold 3-dB bandwidth enhancement for the driver-modulator system is shown. Error-free transmission of 23 Gb/s OOK is achieved with driving electronics of 7.5 GHz bandwidth only. The spectrum narrowing capability of the resonant modulator is also discussed. 40 Gb/s eye and error-free transmission over 9 km SSFM are measured with a reduced occupied bandwidth compared to a standard LiNbO3 modulator. Advantage over standard modulators is therefore demonstrated.