Step 1: Understanding fibre optic communication.
Fibre optic communication relies on light signals transmitted through optical fibres. The medium used for transmitting data is electromagnetic waves, particularly light waves. These waves travel through the fibre core via total internal reflection.
Step 2: Conclusion.
Hence, the type of wave used in fibre optic communication is electromagnetic waves.
\[
\boxed{\text{Electromagnetic waves}}
\]