R. E. Kennedy

Extended continuous-wave supercontinuum generation in a low-water-loss holey fiber

We report on the development of a 2.5 microm core photonic crystal fiber with a substantially reduced water-peak loss around 1.38 microm, which allows extended Raman-soliton supercontinuum generation up to 1.55 microm with a cw ytterbium fiber laser pump source. The resulting broadband, high-spectral-power-density, low-coherence light source can be employed for advanced, submicrometer resolution optical coherence tomography.

20-kW peak power all-fiber 1.57-µm source based on compression in air-core photonic bandgap fiber, its frequency doubling, and broadband generation from 430 to 1450 nm

We demonstrate an ultrashort all-fiber-integrated chirped-pulse amplification system yielding 1-ps pulses with 20 kW of peak power. 40-ps initial pulses generated by an externally modulated laser diode are chirped by self-phase modulation in a conventional fiber, amplified, and compressed in 110 m of air-core photonic bandgap fiber. The compressed pulses are frequency doubled in a periodically poled KTP crystal with up to 48% efficiency and applied to supercontinuum generation in a holey fiber, resulting in a high-power uniform continuum that stretches from 430 to 1450 nm.

High-peak-power femtosecond pulse compression with polarization-maintaining ytterbium-doped fiber amplification

We report the generation of 140 fs pulses with a peak power of up to 270 kW using a fiber pulse source based on a polarization-maintaining ytterbium-doped fiber amplifier and a semiconductor saturable absorber mirror mode-locked fiber laser seed. The seed laser pulses were amplified and chirped in the fiber amplifier and subsequently compressed in an external transmission grating pair. The use of a polarization-maintaining amplifier addresses nonlinear polarization-induced limitations to the obtainable compressed pulse duration and quality that can arise if isotropic fiber amplification is used. Numerical simulations of the system support the experimental measurements and also confirm the role of fiber dispersion in obtaining high-quality compressed pulses.

Ytterbium gain band self-induced modulation instability laser

We demonstrate an ytterbium gain band self-induced modulation instability laser. A highly nonlinear holey fiber is used to provide the anomalous dispersion required for bright soliton generation at 1 microm. The all-fiber integrated source yields a 40 GHz train of 4 ps pulses at a wavelength of 1064 nm.

High-power completely fiber integrated super-continuum sources (Invited Paper)

Advances in high power fibre lasers and amplifiers and in novel non-linear fibres that can be readily integrated with such pumps have led to a family of high power super-continuum sources that extend throughout the complete window of transparency of silica based fibres. The systems have been operated femtosecond, picosecond and nanosecond as well as cw. Average powers of 10’s Watts can be easily achieved, giving flat spectral power densities in excess of 10’s mW per nm from 400 nm to beyond 2.2 μm.

2 W/nm peak-power all-fiber supercontinuum source and its application to the characterization of periodically poled non-linear crystals

We demonstrate a uniform high spectral brightness and peak power density all-fiber supercontinuum source. The source consists of a nanosecond Ytterbium fiber laser and an optimal length PCF producing a continuum with a peak power density of 2 W/nm and less than 5 dB of spectral variation between 590 and 1500 nm. The Watt level per nm peak power density enables the use of such sources for the characterization of non-linear materials. Application of the source is demonstrated with the characterization of several periodically poled crystals.

Aircore fiber based spectral compression of an all fiber integrated ultrashort pulse source

We report on the spectral compression of an all fiber integrated ultrashort pulse source using both transmission grating pairs and aircore photonic bandgap fiber to provide the required negative chirp.

All fiber integrated, kilowatt level, subpicosecond chirped pulse ytterbium amplification system using an aircore photonic bandgap fiber

All fiber integrated chirped pulse amplification at 1.06 mum using an aircore photonic bandgap fiber is demonstrated. The system output pulses have a peak power of 2.3 kW and duration of 740 fs

Fiber integrated femtosecond soliton sources from CW noise

We report on the development of simple, femtosecond soliton sources based on the propagation of CW noise through a highly nonlinear fiber. A method of wavelength extension to the visible is proposed.

Holey fiber based modulation instability laser at 1.06 μm

We report on an Ytterbium gain band, holey fiber based modulation instability laser. The all fiber integrated source produces a 40 GHz train of 4 ps pulses at a wavelength of 1064 nm.