In the realm of structural health monitoring (SHM) for aerospace applications, optical sensors have gained significant prominence due to their ability to deliver real-time measurements of critical parameters, including strain, deformation, temperature, vibration, and pressure. These measurements are essential for evaluating the structural integrity of aerospace components. Numerous optical sensing technologies, such as optical interferometers, are specifically developed for SHM purposes. Among these, acoustic emission (AE) stands out as a vital technique extensively utilized in SHM to identify damage and estimate the remaining service life of aerospace structures. AE arises from the rapid release of energy within a material, generating transient elastic waves, also referred to as stress waves. These emissions, distinguished by unique amplitude and frequency characteristics, are associated with failure mechanisms such as crack growth and deformation, making AE a powerful tool for damage assessment and localization. In this chapter, optical sensors for SHM are introduced, which can be integrated into modern aircraft design enhances safety, reliability, and efficiency, addressing critical challenges associated with aging aircraft and emerging materials like composites.