Effect of Mach-Zehnder modulator´s spectral response on the time-stretch analog-to-digital converter

Summary form only given. Photonic Time Stretch (TS) preprocessing is a promising technique for enhancing the performance of electronic Analog-to-Digital Converters (ADC). In the TS technique, broadband (10-30 nm) nearly-transform-limited pulses are dispersed through a length (L/sub 1/) of a single mode fiber (SMF-28) creating a linear chirp. The RF signal is then imposed onto the chirped carrier in a MZ intensity modulator biased at quadrature point. A second fiber (L/sub 2/) is then used to stretch the modulation envelope. A major difference between the TS and a conventional analog link is the broad bandwidth of the source in the TS system. Because the modulator´s transfer function depends on wavelength, this can distort RF signals. In this paper, we report, for the first time, the impact of the modulator´s wavelength dependence on the achievable dynamic range in a TS ADC system.