Background Compensation of Frequency Interleaved DAC for Optical Transceivers

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 transceivers such as those used in coherent optical communications. Adaptive background techniques for FI-DAC have not been reported so far. They can compensate errors caused by process, voltage, and temperature variations in the technology (e.g., CMOS, SiGe) implementation of the data converters, and therefore ensure high manufacturing yield. Background compensation is important because it does not need to interrupt the normal operation of the transceiver. 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 latter. Simulations show more than 20dB of signal to noise and distortion ratio (SNDR) improvement because of the accurate compensation. Analog mismatch impact elimination is achieved, resulting in a high performance transmitter system.