Fig. 1. Schematic diagram of the proposed silicon photonic MDM-WDM transmitter.

Fig. 2. (a) Schematic diagram of the MRM structure. (b) Cross-sectional view of the phase shifter within the MRM.

Fig. 3. (a) Schematic diagram of the dual-mode GC. (b) Top view of the designed dual-mode GC. (c) Simulated coupling efficiency of the proposed dual-mode GC.

Fig. 4. Microscopic images of the (a) four-channel hybrid MDM-WDM transmitter, (b) the MRM, and (c) the dual-mode GC.

Fig. 5. Measured static transmission spectra of the (a) TE₀-λ₁, (b) TE₁-λ₁, (c) TE₀-λ₂, and (d) TE₁-λ₂ channels.

Fig. 6. Measured transmission spectra around 1550 nm of (a) the TE₀-λ₁ channel and (b) the TE₀-λ₂ channel with heating voltages applied to the MRM₁. (c) Measured transmission spectra around 1550 nm of the TE₀-λ₂ channel with heating voltages applied to the MRM₂. (d) Measured transmission spectra of the TE₀-λ₁ channel under various reverse bias voltages.

Fig. 7. Measured EO-S₂₁ results of the four channels under a 5-V reverse bias voltage.

Fig. 8. (a) Schematic diagram of the high-speed measurement setup. (b) Eye diagrams of the 32 Gbps OOK signals for the four channels on the sampling oscilloscope. (c) Measured BER curves of the 56 Gbps DMT signals for each channel. (d) Corresponding received constellations of four typical subcarriers.

Fig. 9. (a) Schematic diagram of the 3D co-packaged TOSA. (b) Schematic diagrams of the EIC and PIC. (c) Top view and (d) side view of the 3D-packaged EPIC.