Broadband Thin-Film Lithium Niobate Modulator Module Capable of 390 Gb/s Operation

Wideband electro-optic modulators are key components in high-speed data transmission systems. Microwave resonances induced by packaging-related parasitic modes can significantly degrade the bandwidth performance of modulator modules. In this work, we present a high-performance thin-film lithium niobate (TFLN) modulator module featuring a 1.0-mm coaxial connector. The module contains a TFLN modulator chip employing low-k underfill to exhibit an ultra-wide bandwidth exceeding 110 GHz. A series of parasitic-mode suppression strategies are incorporated to ensure resonance-free frequency response for the packaged module, including inner slow-wave electrodes for flexible microwave input layout, a quartz-based grounded coplanar waveguide (GCPW) feedline with metal vias, a parasitic mode suppressor micromachined into the Kovar housing, and short-circuit bonding wires. The packaged modulator module exhibits a flat frequency response with an electro-optic bandwidth of 100 GHz, and supports high-speed data transmission of 130 Gbaud eight-level pulse amplitude modulation (PAM8) over 500 m of standard single-mode fiber in the O-band, corresponding to a maximum data rate of 390 Gbps. This demonstration validates the potential of our module for ultra-high-speed optical communications.