Design Techniques for High Pin Efficiency Wireline Transceivers

Abstract

While the majority of wireline research investigates bandwidth improvement and how to overcome the high channel loss, pin efficiency is also critical in high-performance wireline applications. This dissertation proposes two different implementations for high pin efficiency wireline transceivers. The first prototype achieves twice pin efficiency than unidirectional signaling, which is 32Gb/s simultaneous bidirectional transceiver supporting transmission and reception on the same channel at the same time. It includes an efficient low-swing voltage-mode driver with an R-gm hybrid for signal separation, combining the continuous-time-linear-equalizer (CTLE) and echo cancellation (EC) in a single stage, and employing a low-complexity 5/4X CDA system. Support of a wide range of channels is possible with foreground adaptation of the EC finite impulse response (FIR) filter taps with a sign-sign least-mean-square (SSLMS) algorithm. Fabricated in TSMC 28-nm CMOS, the 32Gb/s SBD transceiver occupies $0.09 mm^{2}$ area and achieves 16Gb/s uni-directional and 32Gb/s simultaneous bi-directional signals. 32Gb/s SBD operation consumes 1.83mW/Gb/s with 10.8dB channel loss at Nyquist rate. The second prototype presents an optical transmitter with a quantum-dot (QD) microring laser. This can support wavelength-division multiplexing allowing for high pin efficiency application by packing multiple high-bandwidth signals onto one optical channel. The development QD microring laser model accurately captures the intrinsic photonic high-speed dynamics and allows for the future co-design of the circuits and photonic device. To achieve higher bandwidth than intrinsic one, utilizing both techniques of optical injection locking (OIL) and 2-tap asymmetric Feed-forward equalizer (FFE) can perform 22Gb/s operation with 3.2mW/Gb/s. The first hybrid-integration directly-modulated OIL QD microring laser system is demonstrated.