Nonlinear amplification in φ-OTDR for distributed acoustic sensing

Abstract

A low-noise φ-OTDR sensor is developed by adding a 2-stage pre-amplification system mixing linear and nonlinear amplification in a 3x3 Michelson interferometric configuration. Its performance is evaluated by deploying it as a distributed acoustic sensing system in a survey well (sampling rate: 10 kHz), showing noise floor levels below 1 nε