Single-Mode All-Chalcogenide Brillouin Fiber Laser

Abstract

Brillouin fiber lasers (BFLs) are most often used as optical signal processing devices to reduce laser noise and increase coherence length [1] . BFLs made of silica typically require hundreds of meters of cavity length to provide the sufficient gain, leading to multi-mode operation. Hence, additional filtering applies to suppress the higher order modes. Realizing single-mode BFLs with small footprint and low threshold power requires a nonlinear medium with a large nonlinearity gain. Chalcogenide (ChG) fibers are excellent candidates for this purpose, with their nonlinearity that is 2-3 orders of magnitude larger than silica. So far, a few BFLs using ChG fibers have been proposed [2] – [4] . However, the proposed BFLs include a resonant cavity formed with standard optical fibers and optical fiber couplers (OFC) that are made of silica glass. Recently, ChG OFCs have been proposed [5] – [6] , providing the possibility to fabricate all-ChG fiber devices. Here, we propose the first all-ChG BFL, as well as the first all-ChG ring cavity. The proposed BFL is single-mode thanks to the short cavity length. The same cavity is also compatible with a wide spectral range of wavelengths owing to the all-ChG ring cavity structure, from the telecommunication band up to the mid-infrared.