Multiple radio frequency measurement with an improved frequency resolution based on stimulated Brillouin scattering with a reduced gain bandwidth

TL;DR

This paper presents a photonic RF measurement method using stimulated Brillouin scattering with reduced gain bandwidth, achieving high accuracy and unprecedented frequency resolution for simultaneous multi-frequency measurements.

Contribution

It introduces a novel SBS-based approach with bandwidth reduction via dual SBS gain and loss, enabling high-resolution, multi-frequency RF measurement.

Findings

Measured RF frequencies from 0.3 to 7.6 GHz with <1 MHz RMS error.

Achieved frequency resolution much lower than 10 MHz, the best in SBS-based RF measurement.

Demonstrated simultaneous multi-frequency measurement capability.

Abstract

A photonic-assisted multiple radio frequency (RF) measurement approach based on stimulated Brillouin scattering (SBS) and frequency-to-time mapping with high accuracy and high-frequency resolution is reported. A two-tone signal is single-sideband (SSB) modulated on an optical carrier via a dual-parallel Mach-Zehnder modulator to construct one SBS gain and two SBS losses for SBS gain bandwidth reduction. The unknown RF signal is also SSB modulated on a carrier that has been modulated by a sweep signal, thus the unknown RF signal is converted to a sweep optical signal along with the sweep optical carrier. The bandwidth-reduced SBS gain spectrum is detected by the sweep optical signals at different specific time, mapping the RF frequencies to the time domain. An experiment is performed. RF frequencies from 0.3 to 7.6 GHz are simultaneously measured with a root mean square error of less than 1 MHz. In addition, the frequency resolution of the measurement can be much lower than 10 MHz, which is now the best result in the RF frequency measurement methods employing the SBS effect.