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

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

Bioresorbable optical fiber Bragg gratings

We demonstrate, for the first time, an inscription and wet dissolution study of Bragg gratings in a bioresorbable calcium-phosphate glass optical fiber. Bragg gratings, with average refractive index changes of 5.8 × 10^−4, were inscribed using 193 nm excimer laser radiation. Results on the dissolution of the irradiated fiber in simulated physiological conditions are presented after immersing a tilted Bragg grating in a phosphate buffered saline solution for 56 h; selective chemical etching effects are also reported. The investigations performed pave the way toward the use of such phosphate glass fiber Bragg gratings for the development of soluble photonic sensing probes for the efficient in vivo monitoring of vital mechanical or chemical parameters

Photorefractive tuning of whispering gallery modes of a spherical resonator integrated inside a microstructured optical fibre

We demonstrate the photorefractive tuning of the whispering gallery modes of a single BaTiO3 microsphere resonator integrated inside a grapefruit-shaped microstructured optical fibre, upon CW laser irradiation at 532 nm while using irradiation intensities up to 5.5 W/cm2. Temporal evolution results of the WGM spectra are provided with respect to the illumination and relaxation conditions applied