The detection and study of vibrations play a fundamental role in the monitoring and safety of major engineering systems. This is especially true in the aerospace sector where the operating environment is hostile and the constraints on weights and dimensions are extremely tight. For these reasons, the research and use of sensors based on optical signal transmission is becoming increasingly important. The opportunity to implement distributed measurements along a single fibre, the small size and weight and the high resistance to electromagnetic interference make this technology an ideal candidate for the development of next-generation aerial platforms. In this paper the operating principles and main concepts behind optical signal transmission are introduced, with particular emphasis placed on the type based on Fibre Bragg Grating (FBG).