Thomas S. Sosnowski

Femtosecond fiber lasers with pulse energies above 10?nJ

A series of experiments aimed at determining the maximum pulse energy that can be produced by a femtosecond fiber laser is reported. Exploiting modes of pulse propagation that avoid wave breaking in a Yb fiber laser allows pulse energies up to 14 nJ to be achieved. The pulses can be dechirped to sub-100-fs duration to produce peak powers that reach 100 kW. The limitations to the maximum pulse energy are discussed.

High-energy femtosecond stretched-pulse fiber laser with a nonlinear optical loop mirror

A stretched-pulse fiber laser with a nonlinear optical loop mirror (NOLM) that produces 100-fs pulses with 1-nJ energy is demonstrated. These results constitute a 30-fold increase in pulse energy over previously reported femtosecond fiber lasers with a NOLM. Compared with previous stretched-pulse lasers, this laser offers a cleaner spectrum and improved stability, with comparable pulse duration and energy. Implications for the construction of truly environmentally stable lasers are discussed.

Energy scaling of mode-locked fiber lasers with chirally-coupled core fiber.

We report a mode-locked dissipative soliton laser based on large-mode-area chirally-coupled-core Yb-doped fiber. This demonstrates scaling of a fiber oscillator to large mode area in a format that directly holds the lowest-order mode and that is also compatible with standard fiber integration. With an all-normal-dispersion cavity design, chirped pulse energies above 40 nJ are obtained with dechirped durations below 200 fs. Using a shorter fiber, dechirped durations close to 100 fs are achieved at pump-limited energies. The achievement of correct energy scaling is evidence of single-transverse-mode operation, which is confirmed by beam-quality and spectral-interference measurements.

3C Yb-doped fiber based high energy and power pulsed fiber lasers

3C fiber technology advances the performance frontier of practical, high-pulse-energy fiber lasers by providing very large core fibers with the handling and packaging benefits associated with single mode fibers. First-generation fibers demonstrate scaling to > 240 W average power coincident with 100-kW peak power in 1-mJ, 10-ns pulses while maintaining single-mode beam quality, polarized output, and efficiencies > 70%. Peak powers over 0.5 MW with negligible spectral distortion can be achieved with sub ns, near-transform-limited pulses. In-development second-generation 3C Yb-fiber based on core sizes around 55 μm1 have produced >8 mJ, 13 ns pulses with peak powers exceeding 600 kW.

Experimental demonstration of SRS suppression in chirally-coupled-core fibers

We experimentally demonstrate suppression of Stimulated Raman Scattering using a spectrally tailored transmission of a large-core effectively-single-mode Chirally-Coupled-Core fiber with a large loss at Stokes wavelengths.

Polarized, 100 kW peak power, high brightness nanosecond lasers based on 3C optical fiber

3C (Chirally-Coupled Core) optical fiber establishes a technological platform for high brightness, power scalable lasers with an engineerable fiber geometry that enables robustly single-mode performance of large core diameter fibers. Here we report the demonstration of robust polarization preserving performance of 35 μm core 3C fiber for short pulse systems. A polarization extinction ratio (PER) of ~ 20 dB is stably maintained with ambient temperatures varying over a 50°C range from a Yb-doped double clad 3C fiber amplifier. We also demonstrate that this high-PER polarization output is insensitive to temperature gradients and mechanical perturbations in the 3C fiber amplifier. The ability to deliver high peak power pulses at high average powers while maintaining exceptional beam quality and a stable polarization state in an easily integrated format makes 3C fiber laser systems extremely attractive for harmonic generation to visible and UV wavelengths.

Scaling mode-locked fiber lasers to high energies using chirally-coupled core fiber

We report energy scaling of mode-locked fiber lasers using chirally-coupled core fiber. Pulse energies above 40 nJ dechirping below 200 fs are demonstrated, as well as dechirped durations around 100 fs at pump-limited energies.

Single-mode fiber source of 0.8-/spl mu/J, 150-fs pulses at 1 /spl mu/m

A Yb fiber laser and amplifier system based entirely on single-mode fiber generates 150-fs pulses with energies up to 0.8 /spl mu/J. This source combines high pulse energy with the simplicity and integrability of single-mode fiber.

High energy amplifier similariton laser based on integrated chirally-coupled core fiber

We present an amplifier similariton laser based on chirally-coupled core fiber. Chirped pulse energies up to 60 nJ are obtained with compressed durations below 90 fs. We demonstrate an integrated pump-signal combiner for chirally-coupled fibers.

High power dissipative soliton laser using chirally-coupled core fiber

We report the energy scaling of mode-locked fiber lasers using a large-mode area chirally-coupled core fiber. This is a demonstration of the scaling of ultrafast fiber oscillators to large cores in an all-solid glass package that holds the lowest order fiber mode while maintaining compatibility with fiber fusion technology. An all-normal dispersion cavity design yields pulse energies above 40 nJ that dechirp to durations below 200 fs. Using lower net dispersion, pulses dechirping close to 100 fs are obtained with pump limited energies. Effectively single-mode operation is confirmed by beam quality as well as spectral interference measurements.