The silicon industry stands as a cornerstone in the realm of modern technology, underpinning an array of innovations that have reshaped the communication paradigm. Among its many contributions, silicon’s integration into photonics has revolutionised optical communications, enabling the development of high-performance devices and systems, and its commercialisation at an industrial level. At the heart of this transformative journey lies the grating coupler, an essential component that facilitates the seamless integration between silicon-based integrated waveguide devices and the vast world of optical fibers and free-space optics. This thesis analyses the design process of a grating coupler and its automatic optimisation.