Multi-Gigabit RF-DAC Based Duobinary/PAM-3 Modulator in 130 nm SiGe HBT

In this work a combined duobinary and PAM-3 (Pulse Amplitude Modulation) modulator is designed and fabricated using a 130 nm silicon germanium process. The RF-DAC based duobinary/PAM-3 modulator covers 95 GHz of bandwidth between 35 GHz and 130 GHz and uses three-valued logic. Together with a power detector, high data rate links can be realized without carrier recovery or phase recovery, thus simplifying the overall design. Data rates up to 30 Gbps is demonstrated using duobinary modulation with a symbol error rate (SER) of 6.4 * 10−6. For PAM-3 modulation data rates up to 28 Gbps is demonstrated with a SER of 1.4 * 10−6. The wide bandwidth and high data rate makes it suitable to be used together with a polymer microwave fiber (PMF) for a low cost and robust system, instead of optic fiber.