# BOTDA using OFDM channel estimation

## TL;DR

This paper introduces a new BOTDA system using IM-DD-OFDM probe signals that eliminates the need for frequency sweep, analyzing PAPR effects and demonstrating high spatial resolution over 2 km fiber.

## Contribution

It presents a novel BOTDA approach with OFDM channel estimation and direct detection, avoiding traditional frequency sweep methods.

## Key findings

- Achieved 25m spatial resolution over 2 km fiber
- Analyzed PAPR effects on BGS recovery
- Demonstrated effective Brillouin frequency shift detection

## Abstract

A novel Brillouin optical time-domain analysis (BOTDA) system is proposed using intensity-modulated optical orthogonal frequency division multiplexing probe signal and direct detection (IM-DD-OOFDM) without frequency sweep operation. The influence of peak to average power ratio (PAPR) of OFDM probe signal on the recovery of Brillouin gain spectrum (BGS) is analyzed in theory and experiment. The complex BGS is reconstructed by channel estimation algorithm and Brillouin frequency shift (BFS) is located by curve fitting of intensity spectrum. The IM-DD-OOFDM BOTDA is demonstrated experimentally with 25m spatial resolution over 2 km standard single mode fiber.

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Source: https://tomesphere.com/paper/1702.02291