Beyond 300 Gbps Short-Reach Links Using TFLN MZMs With 500 mVpp and Linear Equalization

Abstract

Driven by the growing data demand and the stringent power constraints on short-reach datacenter interconnects (DCI), this work compares the driver-less (RF driver-free) transmission performance of thin-film lithium niobate (TFLN) Mach-Zehnder modulators (MZM). Two C-band MZMs (18 / 23 mm) fabricated in a commercial foundry are considered. Using the longer MZM with only linear equalization and ~500 mVpp driving signal, we transmit: (1) 132 Gbaud PAM6 signal (net 309 Gbps) below the 6.7% overhead (OH) hard-decision (HD)-FEC threshold; and (2) 136 Gbaud PAM8 signal (net 342 Gbps) above the 19.02% OH soft-decision (SD)-FEC normalized generalized mutual information (NGMI) threshold of 0.8798 over 500 m of standard single-mode fiber (SSMF). This work demonstrates the feasibility of operating beyond 300 G/lane using TFLN MZMs with CMOS-compatible driving levels.