Spatially Partitioned Doped Fiber for Independently Controllable Dual‐Wavelength Lasing

Dual‐wavelength fiber lasers operating in the 1.0 µm band are of significant interest for applications such as optical frequency synthesis, differential absorption sensing, and multi‐band lidar. However, achieving independently controllable dual‐wavelength emission in a single fiber remains challenging due to ion‐ion interactions and system complexity in conventional co‐doped or multi‐source approaches. In this work, we demonstrate a spatially partitioned doped fiber (SPDF) with a double‐semicircle Yb 3+ ‐ and Nd 3+ ‐doped silicate glass core, in which the two active ions are confined to physically separated semicircular regions within a common core. This spatial partition helps suppress inter‐ion energy transfer while enabling selective excitation using 976 nm pumping for Yb 3+ and 808 nm pumping for Nd 3+ . Using a compact 3.5 cm SPDF segment, switchable laser outputs at 1034 and 1064 nm are achieved, demonstrating independent wavelength control with negligible cross‐response between the two pump channels. This finding indicates that spatial partitioning provides a compact and practical route for independently controllable dual‐wavelength fiber lasers and enables integration into miniaturized fiber laser systems.