High-speed, low-voltage, low-bit-energy silicon photonic crystal slow-light modulator with impedance-engineered distributed electrodes

Silicon modulators in optical transceivers feature high-density integration and low manufacturing cost, but they also need to deliver high speed and low power consumption to meet the demands of future data centers and high-performance computing. This paper demonstrates a significantly improved 64 Gbps silicon Mach–Zehnder modulator incorporating photonic crystal slow-light phase shifters. By employing distributed electrodes and engineering their impedance, electro-optic phase matching and electrical impedance matching were obtained simultaneously, and the driving voltage was reduced to 0.87 V, which is compatible with fin-type field effect transistors and eliminates the need for additional electrical amplifiers. The bit energy of as low as 59 fJ/bit is comparable to that of microring modulators, while this modulator does not require temperature control like that used for microring modulators, due to its wide working spectrum of 6 nm. These results indicate the potential for addressing power issues in next-generation data infrastructures.