We present the design performance validation of an energy-efficient silicon Mach-Zehnder modulator (MZM) with a forward-biased PIN junction by simulation and experiment. With a length of $50~\mu \text{m}$ , the presented MZM exhibits at least four times smaller form factor for the active phase-shifter than the state-of-the-art. Furthermore, we recorded a remarkably low $V_{\mathrm {\pi }}L$ of only 0.0025 $\text{V}\times $ cm. By thermal tuning of an additional heater, segmented with the phase shifter, the measured DC extinction ratio of the MZM was 30 dB. Non-return-to-zero data transmission up to 5 Gb/s and the generation of sinc-shaped Nyquist pulse sequences with a bandwidth of 12 GHz is demonstrated. The very small footprint and power consumption make the presented MZM an ideal choice for various applications like Nyquist pulse generation, parallel analog signal processing, arbitrary waveform generation, etc.
