Compact Fully Integrated Alignment-Free and Linearly Polarized Ho${}^{3+}$ Single-Frequency Waveguide Laser

Abstract

We report, for the first time, a fully integrated Ho${}^{3+}$-doped fluoride glass waveguide laser incorporating a femtosecond laser-inscribed waveguide and waveguide Bragg grating. A line-by-line inscription technique was employed to fabricate the Bragg gratings, yielding highly consistent and reproducible grating characteristics with precise control of the Bragg resonance wavelength. A compact 12.4 mm cavity achieves stable single-frequency lasing at 2062.21 nm with a linewidth of less than 5 MHz. The laser exhibits intrinsically linearly polarized emission. This alignment-free architecture provides a compact and robust platform for integrated mid-infrared single-frequency laser sources.

arXiv comment8 pages, 11 figures