Acoustic sensors are used in Structural Health Monitoring (SHM) for the detection of impacts and strain. However,
secondary damage may result from the initial damage. This secondary damage, such as delamination or cracking, may
not be detectable by the SHM system. This is a significant problem for passive sensing systems, such as those based on
fibre optics, where signals cannot be actively generated to interrogate the structure. The integration of NDE by robotic
agents into a SHM sensor network enables the detection and monitoring of a wider variety of damage. Communicating
via acoustic transmissions represents a wireless communication method for robotic agents to communicate to the SHM
system without the addition of extra hardware, as piezoelectric transducers are commonly used in NDE. The effect of
Carbon Fibre Composites (CFC) on the ability to use acoustic transmission needs to be determined.
We present results for the detection of Acoustic Emissions and Transmissions (AET) in a CFC laminate. The optical
fibre AET detector was a Fibre Bragg Grating (FBG). Two FBG AET sensors were compared, one coupled to the surface
of the carbon fibre sheet, and one embedded within the lay-up. Results compare the transfer function, frequency
response, and transient response of the sensors. The embedded FBG receiver was also used to detect an actively
generated acoustic transmission. A piezoelectric receiver was also used for comparison. The embedded FBG was found
to give significantly better performance in all of the parameters considered for the surface coupled FBG.