2022/11/07 by Alexander T. Bekker, Bekker, Alexander, Gefen Levite +3
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #Advanced Fiber Optic Sensors #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystal and Fiber Optics
paper · pdf · doi:10.48550/arxiv.2211.03485
openalex publication_date 2022/11/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report on the observation of puzzling nonuniform, but ordered, frequency combs in erbium-doped fiber lasers at low temperatures, between 3 K and 14 K. At ~14 K the combs disappear. The combs contain ~240 lines and have nonuniform frequency spacings that starts from ~25 GHz at ~1540.5 nm and decreases, almost monotonically, to ~100 MHz within (1.8-2) nm. We discuss possibilities that they result from enlarged regular mode-comb spacings, from prime numbers-based solitary waves free of four-wave mixing or result from gain gratings. However, we think that the combs originate from multi-lasing lines allowed in inhomogeneous gain broadening, dominant at low temperatures, together with a small power dependent homogeneous broadening part, responsible for the spacing between the lines.