Breaking the bandwidth limit of a high-quality-factor ring modulator based on thin-film lithium niobate

Abstract Growing global data traffic requires high-performance modulators with a compact size, a large bandwidth, a low optical loss, and a small power consumption. A careful trade-off among these parameters usually has to be made when designing such a device. Here, we propose and demonstrate an electro-optic ring modulator on the thin-film lithium niobate platform without compromising between any performances. The device exhibits a low on-chip loss of about -0.15dB with a high intrinsic Q-factor of 7.7×105. Since a pure coupling modulation is employed, the photon life-time is no longer a limiting factor for the modulation speed. A large electro-optic bandwidth is obtained without any roll-off up to 67 GHz. The device, with a footprint of 3.4 mm×0.7 mm, also exhibits a low half-wave voltage of 1.75 V, corresponding to a half-wave voltage length product of 0.35 V∙cm considering the 2-mm long modulation section. Driverless data transmission up to 240 Gb/s is also demonstrated.