Analysis of the effect of jitter and non-idealities on photonic digital-to-analog converters based on Nyquist pulses

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The bandwidth and resolution of the electronic digital-to-analog converters (DAC) and analog-to-digital converters (ADC) of modern-day communication systems defines the link capacity to a large extent. For high analog bandwidths, the performance of state-of-the-art DACs is limited in terms of the effective number of bits (ENOB). A drastic improvement in ENOB might be realizable with photonic based DAC by employing integrated Mach- Zehnder modulators (MZM) and time-domain interleaving. Especially, the optical signal processing of Nyquist pulses with MZM might provide a possible solution to achieve high analog bandwidths with relatively low required electronic and photonic bandwidth. By using optical time interleaving and pulses synthesized by an MZM with a bandwidth of 100 GHz for the modulator and the electronics, sampling rates of 300 GS/s can be achieved. Thus, with standard silicon components available on the market, a compact and low-cost integrated photonic DAC module can easily be realized. The ENOB of such a system is limited by the quality of the Nyquist pulses, which in turn is affected by the jitter of the used signal generator (SG) and MZM nonlinearities. Here we present analytically that an ENOB of more than 8 can be achieved for analog bandwidths greater than 100 GHz by using a low phase noise SG. With experimental validation, we analyze the upper operation limit of such photonic DACs and their dependence on non-idealities of the Nyquist pulses.