Fusion Splicing Soft Glass Microfibers for Photonic Devices

We report fusion splicing nonsilica soft glass microfibers by using single pulses from a CO₂ laser. Splice loss of a 2-μ m-diameter phosphate glass microfiber is around 0.2 dB. By fusion splicing phosphate glass microfibers into closed-loop rings, we demonstrate a microfiber resonator with a Q-factor of about 25 000 and a 1.5-μm-wavelength microring laser with a linewidth of about 0.05 nm. Our results suggest a potential approach to fabricating robust and versatile photonic components or devices out of soft glass microfibers that are excellent hosts for a variety of functional dopants.