Adaptive Background Compensation of FI-DACs with Application to Coherent Optical Transceivers

TL;DR

This paper introduces an adaptive background compensation method for FI-DACs in high-speed digital transceivers, enhancing performance by automatically correcting process, voltage, and temperature-induced errors.

Contribution

It presents the first adaptive background compensation scheme for FI-DACs using a MIMO equalizer and backpropagation, improving manufacturing yield and system robustness.

Findings

Effective compensation of analog impairments demonstrated in simulations

Significant reduction of errors caused by process, voltage, and temperature variations

Enhanced transmitter system performance achieved

Abstract

This work proposes a novel adaptive background compensation scheme for frequency interleaved digital-to-analog converters (FI-DACs). The technique is applicable to high speed digital transceivers such as those used in coherent optical communications. Although compensation of FI-DACs has been discussed before in the technical literature, adaptive background techniques have not yet been reported. The importance of the latter lies in their capability to automatically compensate errors caused by process, voltage, and temperature variations in the echnology (e.g., CMOS, SiGe, etc.) implementations of the data converters, and therefore ensure high manufacturing yield. The key ingredients of the proposed technique are a multiple-input multiple-output (MIMO) equalizer and the backpropagation algorithm used to adapt the coefficients of the aforementioned equalizer. Simulations show that the impairments of the analog signal path are accurately compensated and their effect is essentially eliminated, resulting in a high performance transmitter system.