Second harmonic generation induced by poling in borophosphate bulk and thin film glasses

In the development of high bit-rate capacity in telecom systems, fiber technology and/or integrated glass waveguides provide a means to implement low cost active optical devices with low insertion losses and fiber compatibility. Presently glass-based devices are limited in efficiency and it is of the utmost importance to increase the non-linear optical response. In this context the present investigation compares the induced second-order optical non-linearity of silica and more complex glasses after electro-thermal poling process. The optical responses of infrasil and suprasil silica glasses are compared with those of the calcium borophosphate glasses of composition [1 − x(90%Ca(PO ₃) ₂–10%CaB ₄O ₇) − xNb ₂O ₅] ( x = 0.3; 0.5) using the same experimental conditions for poling, SHG measurements and simulations. In addition the borophosphate glass of composition x = 0.3 has been successfully poled as a thin film deposited on a soda-lime glass. Borophosphate glasses as bulk or thin films exhibit a higher magnitude of the second-order optical response than that of silica. A tentative structural approach of this behavior is discussed.