Time Warps in Photonic Time Stretch ADC and Their Mitigation

TL;DR

This paper presents a high-resolution 10-GHz bandwidth photonic time stretch ADC with distortion correction, achieving record resolution and SNR, and demonstrates concatenation of wavelength interleaved segments for continuous operation.

Contribution

It introduces methods to mitigate time warp distortions and non-linearities in photonic time stretch ADCs, enabling higher resolution and continuous time operation.

Findings

Achieved 7 effective bits resolution at 10 GHz bandwidth.

Demonstrated correction of time warp distortions and non-linearities.

Successfully concatenated 30 wavelength interleaved segments.

Abstract

We demonstrate a 10-GHz bandwidth digitizer with 7-effective bits of resolution and 52dB 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.