Post-melting encapsulation of glass microwires for multipath light waveguiding within phosphate glasses

Abstract: Glass waveguides remain the fundamental component of advanced photonic circuits and with a significant role in other applications such as quantum information processing, light generation, imaging, data storage, and sensing platforms. Up to date, the fabrication of glass waveguides relies mainly on demanding chemical processes or on the employment of expensive ultrafast laser equipment. In this work, we demonstrate the feasibility of a simple, low-temperature, post-melting encapsulation procedure for the development of advanced glass waveguides. Namely, silver iodide phosphate glass microwires (MWs) are drawn from typical splat-quenched samples. Following this, the MWs are incorporated in a controlled manner within previously prepared transparent silver phosphate glass rectangular prisms. The composition of the employed glasses is chosen so that the host phosphate glass has a lower refractive index than the embedded MWs. In such case, the waveguide mechanism relies on the propagation of light inside the encapsulated higher refractive index MWs. Moreover, the presence of silver nanoparticles within the MWs enhances the light transmission due to scattering effects. Waveguide devices with either one or two incorporated MWs were fabricated. Remarkably, in the latter case, the transmission of light of different colors and in multipath direction is possible, rendering the developed waveguides outstanding candidates for various photonic circuits, optoelectronic, and smart sign glass applications.