Designer glasses—Future of photonic device platforms

The intentional inclusion of key atomic elements in a purpose designed glass helps to achieve unprecedented control over the ultrafast laser written circular waveguide morphology and refractive index change. Behavioral response of glass constituents to ultrafast laser in 14 different commercial silicate glasses having various compositions are studied. Viscosity, aluminum to alkaline earth+alkali ratio, and total silicon content within the glass are the prime control factors for producing waveguides with high circularity and refractive index change. Drawing on this knowledge, the designer glass is successfully fabricated from an empirical formula that facilitates maintaining circular waveguide morphology, high refractive index over fast feed rates, and amorphous composition.