Numerical Demonstration of Silicon Micro-Ring Modulator with X-Interleaved PN Junction for High Modulation Efficiency

In order to improve the modulation efficiency of a silicon-based carrier-depletion micro-ring modulator (MRM), a 3D X-interleaved PN junction structure is introduced in the modulation region. The static and dynamic performance of the proposed MRM is compared with the MRM with the previously reported lateral-zigzag PN junction using numerical simulation. Compared to the lateral-zigzag type MRM, the proposed MRM exhibits a 16.7% higher modulation efficiency of 70-pm/V and 2-GHz narrower 3-dB bandwidth of 31-GHz at the bias voltage of −1.0 V. Despite the slightly narrower bandwidth, non-return-to-zero (NRZ) modulation operation indicates that the X-interleaved type MRM can provide 1.7 dB larger dynamic extinction ratio of 4.46 dB at 40-Gbit/s operation with 1.0-V pp driving voltage due to its higher modulation efficiency. It also consumes a 38% lower power of 16.36 fJ/bit to generate a 40-Gbit/s optical signal with an extinction ratio of 4.77 dB. These results indicate that the MRM with X-interleaved PN junction has a potential for application in large-scale high-speed photonic integrated circuits.