Rare-earth-doped glasses and glass-ceramics for integrated optics

In this chapter, we highlight some basic aspects and applications of doped glasses in integrated optics. First, we will briefly summarize the role of rare-earth (RE) ions in integrated optics, reporting some consolidated results presented in the literature as well as some new results concerning the photon management exploited for the luminescence-enhancement mechanisms. Few lines are also assigned to recall the use of the Judd-Ofelt theory in the determination of the spectroscopic parameters, crucial for the design of more novel and efficient photonic devices based on rare earth-doped (RED) glasses. The second section is devoted to the novel and exciting topic of transparent glass ceramics. First, we introduce this kind of materials and we focus the attention of the reader on their important optical, structural, andspectroscopic properties. Of particular interest is the role of tin-dioxide-based glass ceramics as effective sensitizers of the RE ions luminescence. Novel spectroscopic results regarding the Er3+-activated SiO2-SnO2 system are also presented with a discussion about the different possible structures of integrated optics. The different kinds of nanoceramics operating in luminescence quantum yield enhancement are shortly discussed. The differences between the top-down and bottom-up fabrication techniques are presented, as well as some well-consolidated results about the transparent glass ceramics doped with RE ions. In this regard, it is worthy to note the results obtained in a hybrid glass-ceramic fabricated employing an amorphous matrix SiO2-HfO2 loaded by nanoparticles of lithium lanthanum tetraphosphates doped with different concentration of Eu3+ ions. Finally, we conclude the chapter with the perspectives of glass materials for integrated optics.