Embedded-FBG ultrasonic sensing: interrogator configuration comparison

This dataset contains time-domain measurements of ultrasonic responses detected by an embedded fiber Bragg grating (FBG) sensor inside a resin cylindrical specimen. The specimen contains two embedded piezoelectric transducers (PZTs) located at both ends for ultrasonic actuation and reception, and one FBG centered along the cylinder axis (nominal Bragg wavelength λB ≈ 1551.2 nm). The PZT actuation is driven by an arbitrary waveform generator (AWG) and electrical amplifier and is time-synchronized with optical acquisition. The goal of the dataset is to compare the measured electrical outputs obtained from multiple FBG interrogator configurations, including two baseline layouts: (a) broadband light source (BLS) + EDFA + optical circulator + embedded FBG + tunable optical filter + photodiode1, and (b) tunable laser source + optical circulator + embedded FBG + optical attenuator + photodiode2, as well as additional variants formed by combining/removing components (e.g., with/without optical amplification, with/without tunable filter). Data organization: All files are contained under the top-level folder “Optical_FBG_Interrogator_Measurements_Datasets/”, which includes five acquisition groups “DataSet1/” to “DataSet5/”. Each DataSet folder contains (i) “PZT_TX” and “PZT_RX” (electrical oscilloscope traces of actuator drive and received PZT response), (ii) multiple Excel-compatible time-series files corresponding to different interrogator configurations (photodiode/acquisition output), and (iii) supporting metadata such as “Configuration” (text file; includes key settings when available, e.g., laser wavelength, embedded FBG Bragg wavelength, filter center wavelength, oscilloscope sampling/record settings, averaging) and “Actuation_Direction” (image). Some datasets also include the AWG waveform file (e.g., “generated_sine_hamming.arb”) and/or additional subfolders (e.g., tunable-laser related auxiliary data). File naming convention (within each DataSet): configuration files encode the optical chain using compact tags. Common prefixes include “BLS_” for broadband-source-based interrogation and “TunableLaser_” or “TL_*” for tunable-laser-based interrogation. Mid-tags such as “Amp/NoAmp” indicate whether optical amplification (e.g., EDFA stage) was enabled; tags such as “Filter/TF/NoFilter/OF” indicate whether a tunable optical filter (or related filter condition) was present/enabled. Suffixes such as “_PD1” and “_PD2” indicate the photodiode/acquisition path used. Filenames starting with “NoSource/NoBLS/NoLightSource” correspond to control measurements with optical illumination disabled (background/noise reference). Steps to Reproduce: Prepare an embedded-sensor resin cylinder with two PZTs embedded at the two ends and one FBG embedded centered and along the cylinder axis (λB around 1551 nm). Connect the AWG output to an electrical power amplifier and drive one embedded PZT to generate ultrasonic excitation; monitor and record the drive as “PZT_TX”. Connect the opposite embedded PZT to the receive chain and record the received electrical signal as “PZT_RX”. Use a common oscilloscope/DAQ time base so that electrical (PZT_TX/PZT_RX) and optical measurements are time-synchronized. Assemble the optical interrogation path and photodetection: route light through an optical circulator to the embedded FBG and detect the returned/reflected signal with a photodiode connected to the oscilloscope/DAQ. Implement and measure multiple interrogator configurations, including (a) broadband source + EDFA + circulator + FBG + tunable optical filter + photodiode1 (PD1) and (b) tunable laser + circulator + FBG + optical attenuator + photodiode2 (PD2), plus variants by enabling/disabling optical amplification and/or inserting/removing the tunable filter. For each configuration, tune the laser wavelength and/or filter center wavelength near the FBG reflection band and acquire the photodiode time trace under the same actuation condition; save each trace as a separate Excel-compatible file whose filename encodes the configuration tags (source type, Amp/NoAmp, Filter/NoFilter/TF/OF, and PD/acquisition path). For each acquisition group, save the configuration notes (laser wavelength, FBG Bragg wavelength, filter center wavelength when applicable, oscilloscope sampling/record settings and averaging if available) into the “Configuration” text file, and include the “Actuation_Direction” image to document orientation/definition used during measurement. Repeat across DataSet1–DataSet5 (e.g., different sessions, tuning conditions, or configuration subsets) while maintaining consistent naming and synchronized recording so results can be compared across interrogator architectures.