Time warps in photonic time stretch ADC and their mitigation

Abstract

We demonstrate a 10-GHz bandwidth digitizer with 7-effective bits of resolution and 52 dB SFDR, using photonic time stretch technique. To the best of our knowledge, this is the highest resolution analog-to-digital converter (ADC) of the same bandwidth, with at least an order of magnitude higher SNR than previously achieved. This is made possible by correction of distortion due to time warps, and non-linearities due to wavelength dependent bias variation in the Mach-Zehnder modulator. We also demonstrate concatenation of 30 wavelength interleaved time segments with high fidelity on the path to achieving continuous time operation.