Scalable Integration of Multiple Graphene Electro-Absorption Modulators with Silicon Photonics for High-Speed Data Transmission

This study presents a novel approach to integrating multiple graphene electro-absorption modulators (EAMs) with functional silicon photonics circuits. Our approach involves the use of three five-channel wavelength division multiplexing (WDM) transmitters, each consisting of five graphene-Si EAMs designed for TE-polarized light and Si-based second-order microring resonators (MRRs) for wavelength multiplexing. We demonstrate uniform and hysteresis-free performance across all 15 graphene EAMs by employing up-scalable fabrication processes and a passivation-first approach to encapsulate the graphene layer.

The three WDM transmitters were fabricated with varying waveguide widths and device lengths of the EAMs. The first and second transmitters reported an extinction ratio (ER) of 5.5 dB and 5.6 dB, respectively, across a 10 nm bandwidth for five identical 100-ﾵm-long devices with 500-nm- and 600-nm-wide waveguides. The third transmitter, with 150-ﾵm-long EAMs, achieved an ER of 8.1 dB. Open-eye diagrams were measured at 25 Gb/s using 2.5Vpp on each of the five channels of the three WDM transmitters, demonstrating potential for data transmission at 5 x 25Gb/s.

Compared with our previous results presented in Ref. [27], our study shows an additional channel and more detailed device characterization. This demonstration of the integration of multiple graphene EAMs with functional silicon photonics circuits represents a significant advancement in the field of optical communication, with potential applications in high-speed data transmission and optical interconnects in future computing systems.