White Light Generation From YAG:Ce‐Doped Phosphate Glass‐Based Composite Fibers

Abstract The growing demand for next‐generation lighting technology is driving efforts to develop white light‐emitting fibers for potential applications in medical endoscopy, sensing, telecommunication, and integrated photonics. In this work, a new white light‐emitting composite fiber based on YAG:Ce 3+ phosphors embedded in a phosphate glass is developed. The glass matrix composition is precisely tailored to enhance the thermal stability of the glass to allow fiber drawing while matching the refractive index with the phosphors to ensure the transparency of the composite. Comprehensive analyses of the spectroscopic and structural properties reveal significant interfacial reactions between the glass and YAG:Ce 3+ phosphor particles during composite preparation, including phase changes, elemental diffusion, and partial decomposition. Despite these effects, the YAG:Ce 3+ phosphors retain their white light emission properties throughout both preform melting and fiber drawing. Light propagation in the fiber, despite the presence of the phosphors in the fiber, as well as white light emission upon blue excitation are demonstrated.