@article{marashi_bradford_peters_2023, title={Laser Doppler vibrometry measurements of acoustic attenuation in optical fiber waveguides}, volume={62}, ISSN={["2155-3165"]}, DOI={10.1364/AO.483827}, abstractNote={Fiber Bragg grating (FBG) sensors have been widely applied for structural health monitoring applications. In some applications, remote bonding of the optical fiber is applied, where ultrasonic waves are coupled from the structure to the optical fiber and propagated along the fiber to the FBG sensor. The distance that this signal can propagate along the optical fiber without decaying below a threshold value can be critical to the area of the structure that can be monitored per sensor. In this paper, we develop a method to measure the acoustic mode attenuation of fiber waveguides based on laser Doppler vibrometry (LDV) that is independent of the fiber type. In order to validate the method, we compare attenuation measurements on single-mode optical fibers using both the LDV and FBG sensor methods. Once the method is validated, experimental measurements of different coated and uncoated optical fibers are performed to quantify the role of the fiber diameter on the attenuation coefficient. As the radius of the waveguide decreases, the signal attenuation increases exponentially.}, number={16}, journal={APPLIED OPTICS}, author={Marashi, Cameron Sepehr and Bradford, Philip and Peters, Kara}, year={2023}, month={Jun}, pages={E119–E124} }
 @article{kim_marashi_wee_peters_2021, title={Acoustic wave coupling between optical fibers of different geometries}, volume={60}, ISSN={["2155-3165"]}, DOI={10.1364/AO.441494}, abstractNote={In this study, we investigate coupling of acoustic guided waves from different types of input fibers, through a bonded coupler, to an optical fiber. These acoustic waves can then be detected with conventional fiber Bragg gratings (FBGs). The input waves are measured using a high-resolution 3D laser Doppler vibrometer, and the output waves in the optical fiber are measured using an FBG. We demonstrate that the wave coupling between two waveguides varies with the cross-sectional area and the modulus of elasticity of the fibers.}, number={36}, journal={APPLIED OPTICS}, author={Kim, Jee Myung and Marashi, Cameron and Wee, Junghyun and Peters, Kara}, year={2021}, month={Dec}, pages={11042–11049} }
 @article{kim_marashi_wee_peters_2021, title={Investigation on acoustic wave transfer variation between fibers of different diameters and types using acoustic coupler}, volume={11591}, ISSN={["1996-756X"]}, DOI={10.1117/12.2584249}, abstractNote={When using fiber Bragg grating (FBG) sensors in structural health monitoring (SHM) applications, one of the drawbacks is that the sensor location is fixed once it is installed and it is difficult to extend an already existing system. The use of an acoustic coupler to transfer fiber guided traveling waves from one fiber to another could resolve this issue as the system could be modified for extension. In this study, we investigate the coupling of optical fiber guided waves between two different types of fibers through an acoustic coupler. Specifically, input waves are launched into an input fiber and coupled to an output fiber through the acoustic coupler. The input waves are measured using a high-resolution 3D laser Doppler Vibrometer (LDV) and the output waves from the output fiber are measured using an FBG. We demonstrate that the wave coupling between two fibers varies with the cross-sectional area of the input fiber.}, journal={SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2021}, author={Kim, Jee Myung and Marashi, Cameron and Wee, Junghyun and Peters, Kara}, year={2021} }