Low-Threshold, Single-Mode, Compact Brillouin/Erbium Fiber Ring Laser

In this paper, we derive a numerical model to analyze the compact Brillouin/erbium fiber laser with a short commercialized normal erbium-doped fiber (EDF) as both the Brillouin and linear gain media. The effects of the 980 nm pump power, the Brillouin pump power, the EDF length, and the output coupling ratio on the BEFL output power characteristics are simulated. The theoretical results predict that a short commercialized normal EDF is capable for a high-power low-threshold compact BEFL. Based on the theoretical analyses, a BEFL using only 4 m normal EDF as the gain medium is designed and constructed. The measured results demonstrate that this BEFL presents low pump threshold (~20 mW), high output power (> 10 mW), single-mode operation and low relative intensity noise (-120 dB/Hz). This BEFL shows potential applications in distributed Brillouin fiber sensors, interferometric fiber sensors, and coherent optical communications, etc.