90 Gbit/s 4-level pulse-amplitude-modulation vertical-cavity surface-emitting laser driver integrated circuit in 130 nm SiGe technology

This paper presents the design and measurements of a 4-level pulse-amplitude-modulation (4-PAM) vertical-cavity surface-emitting laser (VCSEL) driver integrated circuit (IC) for short-range, high-speed optical communications. The IC is fabricated in 130 nm SiGe technology. Open electrical and optical eye diagrams are reported at 90 Gbit/s and 40 Gbit/s, respectively. The driver consumes only 177 mW of power from a dual supply voltage of 2.0 and 3.35 V including the VCSEL. The optical bit error rate (BER) was tested at 30 Gbit/s showing an error-free connection for one of the two channels. The design is inductor-less and the active area occupies only 150 μm × 150 μm. To the best of the authors' knowledge this is the fastest 4-PAM VCSEL driver IC implemented on silicon.