8-<i>λ</i> × 50 Gbps/<i>λ</i> Heterogeneously Integrated Si-Ph DWDM Transmitter

Abstract

We demonstrate a 3-D heterogeneously integrated dense wavelength-division multiplexing (DWDM) silicon-photonic transmitter simultaneously modulating eight 200-GHz spaced wavelengths at 50 Gbps/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> each, to deliver an aggregate per-fiber bandwidth of 400 Gbps. All necessary <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$O$ </tex-math></inline-formula> -band optical components are fully integrated on the photonic integrated circuit (PIC), including an eight-wavelength laser array, a broadband semiconductor optical amplifier (SOA), and eight microring modulators (MRMs). Eight 50-Gbps non-return-to-zero (NRZ) modulator drivers, capable of delivering 2- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\mathrm {pp}}$ </tex-math></inline-formula> modulation voltage, are integrated in a 28-nm CMOS electronic IC (EIC). The EIC also includes a thermal control unit (TCU) to align the eight MRMs to the eight laser wavelengths by appropriately tuning integrated MRM heaters. The measured energy efficiency at 50 Gb/s of the high-speed electronics, including serializer overhead, is 1.17 pJ/bit.