• Ultrafast Fiber Optics

• Spatiotemporal Solitons

• Semiconductor Nanocrystals

Ultrafast Fiber Lasers and Amplifiers

Fiber lasers offer crucial advantages compared to their solid-state counterparts with their compact size and robust performance, but several applications require higher energy and shorter pulses than available from current designs. Because of the small confinement area of light in the fiber, high intensity pulses can produce several nonlinear and thermal effects. Our research involves developing methods to produce high intensity pulses despite these nonlinearities. One such example involves balancing the optical nonlinearity with the group-velocity dispersion of the fiber in order to produce a soliton. Fiber laser research combines investigations into fundamental soliton and nonlinear propagation with engineering to produce stable and practical systems to be used outside of a research lab.

Recent contributions

• Self-similar pulses in fiber lasers
• Dissipative solitons in all-normal dispersion fiber lasers
• Giant-chirp oscillators for direct amplification
• 10 cycle-pulses or Watt level powers directly from fiber oscillators
• Femtosecond fiber source for two-photon microscopy and picosecond fiber source for CARS imaging

Applications

• Time-resolved studies in chemistry
• Novel imaging techniques in biology
• Optical communications
• Precision material processing
• Ocular surgery

fig.1 Left: Schematic of a fiber laser with dispersion management. Right: Compact prototype laser


fig.2 Calculated power spectrum, temporal intensity and phase, and evolution of a self-similar pulse in a laser. (Ref 7)


fig.3 Comparison of analytic theory and experiment for a dissipative soliton fiber oscillator. Output spectra are shown in the top row and interferrometric autocorrelations are in the bottom. (Ref 3)


fig.4 Box schematic and output pulse data for an amplified giant-chirp oscillator. (Ref 4)


fig.5 A 31 nJ, 70 MHz repetition rate, 2.2 W average power fiber laser with 80 fs pulses with 200 kW peak power after dechirping outside the laser. (a) Output spectrum. (b) Measured intensity autocorrelation. Inset: measured interferometric autocorrelation. (c) RF spectrum, 1 MHz span. (d) RF spectrum, 1 GHz span. From (Ref 2)


fig.6 CARS fiber laser system and images: (a) CARS image at the CH2 stretching frequency W=2845 cm-1 showing the lipid distribution in the stratum corneum of wild-type mouse skin. (b) CARS image of the lipid distribution in the seba- ceous gland 30 um deep in tissue. Scale: 20 um. (Ref 1)

References

1. K. Kieu, B. G. Saar, G. R. Holtom, X. S. Xie, and F. W. Wise. High-power picosecond fiber source for coherent raman microscopy. Optics Letters, 34(13):2051-2053, July 2009.
2. K. Kieu, W. H. Renninger, A. Chong, and F. W. Wise. Sub-100 fs pulses at watt-level powers from a dissipative-soliton fiber laser. Optics Letters, 34(5):593-595, Mar. 2009.
3. W. H. Renninger, A. Chong, and F. W. Wise. Dissipative solitons in normal-dispersion fiber lasers. Physical Review a, 77(2), Feb. 2008.
4. W. H. Renninger, A. Chong, and F. W. Wise. Giant-chirp oscillators for short-pulse fiber amplifiers. Optics Letters, 33(24):3025-3027, Dec. 2008.
5. A. Chong, J. Buckley, W. Renninger, and F. W. Wise, "All-normal-dispersion femtosecond fiber laser," Opt. Express, 14, 10095 (2006).
6. J. Buckley, S. W. Clark, F. W. Wise; "Generation of 10-cycle pulses from an ytterbium fiber laser with cubic phase compensation". Opt. Lett. 31, 1340 (2006).
7. F. Ö. Ilday, J. Buckley, W. Clark, and F. Wise. Self-similar evolution of parabolic pulses in a laser. Physical Review Letters, 92, 213902 (2004).