Low cost O-band inter-datacenter interconnect utilizing a 4-bit resolution digital-to-analog converter for PAM-4 signal generation.

Abstract

In this paper, we experimentally demonstrate the transmission of a 100 Gb/s/λ PAM-4 signal over a 40/80-km single mode fiber (SMF) in the O-band utilizing a 4-bit resolution digital-to-analog converter (DAC) for signal generation. Low resolution DACs are preferred to meet the requirement of low-cost criteria of datacenter interconnects (DCIs). However, large quantization noise introduced by low resolution DACs will deteriorate system performance significantly. Noise shaping (NS) technique is investigated to reduce the quantization noise within the PAM-4 signal band. The experimental results show that the bit error ratio (BER) performance of the signal generated by 4-bit resolution DAC and NS technique will approach that of the signal generated by the 8-bit resolution DAC in the 40/80-km optical fiber transmission system of a 50 Gbaud PAM-4 signal in the O-band, which indicates that our proposed scheme operating in the O-band with a 4-bit resolution DAC and NS technique is a promising candidate for 100 Gbit/s/λ beyond a 40-km Inter-DCI.