Fig. 1. (a) Simulated optical bandwidth, electrical bandwidth, and EO bandwidth of the MRM with different doping concentrations, respectively. (b) Simulated EO bandwidth with optical peaking and extinction ratio (ER) of the MRM with different detuning wavelengths. The ER is simulated with the 3V_pp and 4.5 V reversed-bias voltage.

Fig. 2. (a) Schematic for the high-performance MRM. (b) PN junction in the MRM indicated by dashed square in (a). (c) Microscope picture of the proposed MRM.

Fig. 3. (a) Normalized optical transmission by varying the reversed-bias voltages. (b) Extracted insertion loss (IL) and ER with different working wavelength with driving voltage of 3Vpp.

Fig. 4. Measured EO response with 2 V reversed-bias voltage. The EO bandwidths of 110, 91, 79, 65, and 52 GHz are measured with the detuning wavelength Δλ of 0.326, 0.269, 0.24, 0.183, and 0.115 nm, respectively.

Fig. 5. Experimental setup of the transmission based on the MRM. Tx, transmitter; Rx, receiver; DSO, digital storage oscilloscope; AWG, arbitrary wave generator; PC, polarization controller; PD, photodetector; EA, electrical amplifier; VOA, variable optical attenuator; SSMF, standard single-mode fiber; EQ, equalization; NN, neural network; NLC, nonlinear compensation.

Fig. 6. Measured BER for 110, 115, and 120 Gb/s NRZ at different received optical power. Inset: eye diagram after equalization of 120 Gb/s NRZ signal.

Fig. 7. (a) Measured BER for BtB and after 2 km SSMF transmission with different data rates for PAM-4 signal of the MRM. Inset: diagram of 220 Gb/s PAM-4 signal. (b) Measured BER for 200 Gb/s PAM-4 signal at different received optical powers. Inset: diagram of 200 Gb/s PAM-4 signal.

Fig. 8. (a) Measured BER for BtB and after 2 km SSMF transmission with different data rates for PAM-8 signal of the MRM. Inset: diagram of 240 Gb/s PAM-8. (b) Calculated BER for 180 Gb/s PAM-8 signal at different received optical powers. Inset: diagram of 180 Gb/s PAM-8.

Table 1. Performance Comparison of High-Speed EO Modulators