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

Abstract

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.