Research Results 18


Singlemode Raman lasing in a multimode graded-index fiber with direct diode pumping

Generation of fiber Raman laser with direct diode pumping has been obtained for the first time in the spectral range of <1 micron, where conventional fiber lasers practically do not work. It has been shown that the Raman conversion in a cavity formed in graded-index fiber by special fiber Bragg gratings (FBGs), is accompanied by the beam quality improvement from Мp2~20 (multimode pump radiation at 915 nm) to Мs2~1,2 (singlemode generation at 954 nm). The main contribution to the effect is provided by the weak (R~4%) output FBG, which is formed by femtosecond laser selectively in the central part of the graded-index fiber core. The slope efficiency reaches ~40% at the output power level of >10 W. The opportunite to operate without output mirror (using Rayleigh scattering distributed feedback instead) has been also demonstrated. The obtained levels of power and beam quality enable efiicient frequency doubling of the generated radiation. Thus, new type of fiber lasers operating in near-IR and visible range has been proposed and realized, which is interesting for biomedical diagnoctics, laser dysplays and other applications.


  1. S.I Kablukov, E.I. Dontsova, E.A. Zlobina, I.N. Nemov, A.A. Vlasov, and S.A. Babin, An LD-pumped Raman fiber laser operating below 1 μm, Laser Phys. Lett. 10, 085103 (2013).
  2. S.A. Babin, E.I. Dontsova, and S.I. Kablukov. Random fiber laser directly pumped by a high-power laser diode, Opt. Lett. 38, 17, 3301-3303 (2013).
  3. E.A. Zlobina, S.I. Kablukov, M.I. Skvortsov, I.N. Nemov, and S.A. Babin, 954 nm Raman fiber laser with multimode laser diode pumping, Laser Phys. Lett. 13, 035102 (2016).
  4. S.I. Kablukov, E.A. Zlobina, M.I. Skvortsov, I.N. Nemov, A.A. Wolf, A.V. Dostovalov and S.A. Babin, Mode selection in a directly diode-pumped Raman fibre laser using FBGs in a graded-index multimode fibre, Quantum Electron., 46 (12), 1106-1109 (2016).
  5. E.A. Zlobina, S.I. Kablukov, A.A. Wolf, A.V. Dostovalov, and S.A. Babin, Nearly singlemode Raman lasing at 954 nm in a graded-index fiber directly pumped by a multimode laser diode, Opt. Lett. 42 (1), 9-12 (2017).


Self-sweeping single-frequency fiber laser

A fiber laser with frequency tuning based on new physical principles is demonstrated. A formation in active medium of dynamic spatial gain and refractive index gratings by a standing wave field leads to the generation of sequence of pulses, which equally spaced in time and frequency domain. Each pulse has a spectral width of less than 1 MHz and has the same phase as previous one. The possibility of practical applications of the source for interrogation of fiber sensors based on Bragg gratings and for short pulse synthesis by coherent combining of the sequence is proved. The simplicity and robustness are additional benefits of the laser.


  1. Lobach I.A. et al., Self-scanned single-frequency operation of a fiber laser driven by a self-induced phase grating, Laser Phys. Lett., 11, No. 4, 045103 (2014).
  2. Lobach I.A. et al., Single-frequency Bismuth-doped fiber laser with quasi-continuous self-sweeping, Opt. Express, 23, 24833-24842 (2015).
  3. Lobach I.A. et al., Fourier synthesis with single-mode pulses from a multimode laser, Opt. Lett., 40, 3671-3674 (2015).
  4. Lobach I.A., Kablukov S.I., Application of a self-sweeping Yb-doped fiber laser for high-resolution characterization of phase-shifted FBGs, J. Lightwave Technol., 31, No. 18, 2982-2987 (2013).