Fig. 1. (a) Schematic of the single-drive push-pull MIM. The inset shows the cross section of the modulation arms. (b) An SEM image of the fabricated MIM. The insets show the zoom-in images of the 2×2 MMI coupler and the end Sagnac loop reflectors.

Fig. 2. (a) Normalized transmission spectra of the MIM under various reverse bias voltages. The inset shows the passive spectrum covering one FSR. (b) The extracted phase shift as a function of the reverse bias voltage. The red line is a fitting curve.

Fig. 3. (a) EE S11 small signal RF response of the TWE. (b) The EO S21 response of the MIM.

Fig. 4. Experimental setup for the high-speed optical modulation test. TL: tunable laser; PC: polarization controller; DUT: device under test; VOA: variable optical attenuator. The optical and electrical paths are represented by the solid and dashed lines, respectively. The dotted red box in the output upper branch shows the BER measurement setup.

Fig. 5. Measurement results for the 30 Gb/s BPSK modulation with (a) an eye diagram, (b) a constellation diagram, and (c) a demodulated eye diagram.

Fig. 6. Measured eye diagrams for (a) 18 Gb/s OOK, (b) 20 Gb/s OOK, (c) 18 Gbaud PAM-4, and (d) 20 Gbaud PAM-4 modulations.

Fig. 7. BER of the 20 Gb/s OOK modulated signal as a function of the OSNR (0.1 nm noise bandwidth) for the MIM.