Power Scaling in High Speed Analog-to-Digital Converters using Photonic Time Stretch Technique

TL;DR

This paper explores how photonic time-stretch techniques can maintain constant energy efficiency in high-speed ADCs up to 10 GHz, overcoming electronic limitations and reducing power dissipation.

Contribution

It demonstrates that photonic time-stretch can keep the figure of merit constant at high frequencies, enabling high-resolution, low-power ADCs beyond electronic speed limits.

Findings

FOM increases linearly with bandwidth in traditional ADCs

Photonic time-stretch maintains constant FOM up to 10 GHz

Optics can reduce power and increase bandwidth in high-speed ADCs

Abstract

Factors that contribute to the rapid increase in power dissipation as a function of input bandwidth in high speed electronic Analog-to-Digital Converters (ADCs) are discussed. We find that the figure of merit (FOM), defined as the energy required per conversion step, increases linearly with bandwidth for high-speed ADCs with moderate to high resolution, or equivalently, the power dissipation increases quadratically. It is shown that by use of photonic time-stretch technique, it is possible to have ADCs in which this FOM remains constant for up to 10 GHz input RF frequency. Using this technique, it is also possible to overcome the barrier to achieving high resolution caused by clock jitter and speed limitations of electronics in such ADCs. Use of optics is actively being pursued for reducing power dissipation and achieving higher data-rates for board-level and chip-level serial communication links. In the same manner, we expect that optics will also help in reducing power dissipation in high-speed ADCs in addition to providing broader bandwidths.