Ultra-compact low-voltage and slow-light MZI electro-optic modulator based on monolithically integrated photonic crystal

In this paper, we study an ultra-compact slow-light MZI electro-optic modulator with low voltage and high modulation bandwidth by simulation. The proposed device is totally based on monolithic integrated lithium niobate (LiNbO3) photonic crystal (PC). A slow light line defect waveguide forms the interaction region. The splitter–combiner with high transmission consists of a PC Y-junction and two 60° bends. Meanwhile, with a step PC taper we significantly enhance the coupling to the slow light mode. And we finally realize an integrated modulator embedded in a monolithic photonic crystal. The whole length of the device is 91.59μm, the half-wave drive voltage is as small as 0.66V and the high modulation bandwidth can achieve up to 100 GHz in theory. Besides, the modulator covers over 22.3nm optical bandwidth at telecom wavelength range.