Recent advances in the application of glassy materials in planar and fibre-based photonic structures have led to novel devices and components that go beyond the original thinking of the use of glass in the 1960s, when glass fibres were developed for low-loss, optical communication applications. Exploitation of the material's compositional flexibility, combined with the ability to tailor all aspects of its size, shape, & physical properties, as well as its behaviour when exposed to all forms of electromagnetic radiation, has led to numerous breakthroughs. Thus, for the purposes of this review, the discussion has been divided to highlight issues of material composition and form and how both impact device function, focusing on the advances made within the past decades.
