## Abstract

We report on an amplitude-division-multiplexed interferometric
sensor array for locating acoustic emission. Preliminary
experiments were carried out with a modified Mach–Zehnder
interferometer consisting of two sensing arms and a reference arm and
demonstrated a one-dimensional location accuracy of a few
centimeters. The system can be extended for two- and
three-dimensional location of acoustic emissions by the addition of one
or two more sensing arms, respectively, in the
interferometer.

© 2001 Optical Society of America

Full Article |

PDF Article
### Equations (9)

Equations on this page are rendered with MathJax. Learn more.

(1)
$${E}_{t}\equiv {E}_{r}+\sum _{i=1}^{N}{E}_{i},$$
(2)
$${E}_{i}={E}_{{0}_{i}}exp\left(-j{\mathrm{\varphi}}_{i}\right),$$
(3)
$${E}_{r}={E}_{{0}_{r}}exp\left(-j{\mathrm{\varphi}}_{r}\right),$$
(4)
$${I}_{\mathit{ir}}=2\sum _{i=1}^{N}{E}_{i}{E}_{r}cos{\mathrm{\theta}}_{i}cos\left({\mathrm{\varphi}}_{i}-{\mathrm{\varphi}}_{r}\right),$$
(5)
$${I}_{\mathit{ij}}=2\sum _{i=1,ji}^{N}{E}_{i}{E}_{j}cos{\mathrm{\theta}}_{\mathit{ij}}cos\left({\mathrm{\varphi}}_{i}-{\mathrm{\varphi}}_{j}\right).$$
(6)
$$\mathrm{\Delta}{\mathrm{\varphi}}_{i}=n\mathrm{\eta}{\mathit{kL}}_{i}P,$$
(7)
$$\mathrm{\eta}\equiv -\frac{1-2\mathit{\nu}}{E}+\frac{{n}^{2}\left(1-2\mathit{\nu}\right)}{2E}\left(2{p}_{12}+{p}_{11}\right),$$
(8)
$${P}_{0}\left(t\right)=S\left(t\right)\mathrm{rect}\left(t,0,T\right),$$
(9)
$${P}_{i}\left(t\right)={\mathrm{\xi}}_{i}S\left(t-{\mathrm{\tau}}_{i}\right)\mathrm{rect}\left(t,{\mathrm{\tau}}_{i},T+{\mathrm{\tau}}_{i}\right),$$