Embedded digital phase noise analyzer for optical frequency metrology

TL;DR

This paper presents an embedded digital phase noise analyzer using a dual-core microcontroller for real-time optical signal processing, offering a compact, configurable alternative to FPGA-based systems for optical metrology applications.

Contribution

It introduces a novel embedded system architecture for optical phase noise analysis, enabling real-time processing with high flexibility and lower complexity compared to traditional FPGA solutions.

Findings

Successfully implemented IQ demodulation and phase noise analysis

Achieved real-time processing of optical signals over long distances

System is compact, configurable, and suitable for field deployment

Abstract

Digital signal processing (DSP) is supporting novel in-field applications of optical interferometry, such as in laser ranging and distributed acoustic sensing. While the highest performances are achieved with field-programmable gated arrays (FPGAs), their complexity and cost are often too high for many tasks. Here, we describe an alternative solution for processing optical signals in real-time, based on a dual-core 32-bit microcontroller. We implemented in-phase and quadrature (IQ) demodulation of optical beat-notes resulting from the interference of independent laser sources, phase noise analysis of deployed optical fibers covering intercity distances, and synchronization of remote acquisitions via optical trigger signals. The embedded architecture can efficiently accomplish a large variety of tasks in the context of optical signal processing, being also easily configurable, compact, and upgradable. These features make it attractive for applications that require long-term, remotely operated, and field-deployed instrumentation.