Highly Efficient Micro-Joule All-Fiber Ultrafast Raman Amplifier at 1120-nm

• Published in: IEEE photonics technology letters Vol. 35; no. 19; pp. 1063 - 1066
• Main Authors: Liu, Kun, Xu, Minghang, Zhao, Hong, Zhang, Dayong, Ci, Mingru, Li, Xiaohui
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplifiers; Energy conversion efficiency; fiber laser; Fiber lasers; fiber nonlinear optics; Frequency shift; Optical fiber amplifiers; Optical fiber dispersion; Optical fiber polarization; Pulse duration; Pump lasers; Raman laser; Raman lasers; Raman spectra; Solitary waves; Stimulated emission; Ultrafast optics
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2023.3296775

We report a high-efficiency, high-energy, all-fiber, polarization maintaining, ultrafast Raman amplifier. The Raman laser consists of a ps pump seed and two pump/Raman fiber amplifiers. The ultrafast Raman seed is generated via stimulated Raman scattering in the first pump/Raman amplifier and amplified in the second pump/Raman amplifier. Eventually, Raman pulses centered at 1120-nm with a average power of 93-W, a pulse energy of 2.56-<inline-formula> <tex-math notation="LaTeX">\mu \text{J} </tex-math></inline-formula>, a pulse width of 19.2-ps are delivered. The conversion efficiency (the ratio of the Raman pulse energy to the total energy) is ~89.5%, comparable to the conversion efficiency achieved by Raman fiber lasers based on soliton self-frequency shift. This simple and compact scheme provides a pathway for the generation of high-power, high-energy all-fiber, ultrafast Raman pulses with high conversion efficiency at 1.1-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula>.