J.R. Taylor

Direct continuous-wave measurement of n2 in various types of telecommunication fiber at 1.55 μm

A method for measuring the nonlinear refractive index of optical fibers with an error of less than 5% is demonstrated. The technique is based on measuring the nonlinear phase shift experienced by a dual-frequency beat signal, permitting a simple, highly sensitive, accurate, repeatable, and easily automated measurement procedure and sampling. Measurements of the nonlinear coefficient in standard telecommunication, dispersion-shifted, and a number of dispersion-compensated fibers are presented.

Supercontinuum self-Q-switched ytterbium fiber laser

We have discovered a new mechanism for passive Q switching of fiber lasers. 10-kW peak power pulses with ~2-ns pulse widths are reported from a diode-pumped ytterbium-doped fiber laser. The laser generates a high-brightness Raman-dominated supercontinuum spectrum covering the complete window of transparency of silica fiber in the infrared from 1.06 to 2.3 mum.

Zero-dispersion wavelength decreasing photonic crystal fibers for ultraviolet-extended supercontinuum generation

We report the fabrication of photonic crystal fibers with a continuously-decreasing zero-dispersion wavelength along their length. These tapered fibers are designed to extend the generation of supercontinuum spectra from the visible into the ultraviolet. We report on their performance when pumped with both nanosecond and picosecond sources at 1.064 microm. The supercontinuum spectra have a spectral width (measured at the 10 dB points) extending from 0.372 microm to beyond 1.75 microm. In an optimal configuration a flat (3 dB) spectrum from 395 to 850 nm, with a minimum spectral power density of 2 mW/nm was achieved, with a total continuum output power of 3.5 W. We believe that the shortest wavelengths were generated by cascaded four-wave mixing: the continuous decrease of the zero dispersion wavelength along the fiber length enables the phase-matching condition to be satisfied for a wide range of wavelengths into the ultraviolet, while simultaneously increasing the nonlinear coefficient of the fiber.

Supercontinuum generation in optical fibers

1. Introduction and history J. R. Taylor 2. Supercontinuum generation in microstructure fiber - an historical note J. K. Ranka 3. Nonlinear fiber optics overview J. C. Travers, M. H. Frosz and J. M. Dudley 4. Fiber supercontinuum generation overview J. M. Dudley 5. Silica fibers for supercontinuum generation J. C. Knight and W. Wadsworth 6. Supercontinuum generation and nonlinearity in soft glass fibers J. H. V. Price and D. J. Richardson 7. Increasing the blue-shift of a picosecond pumped supercontinuum M. H. Frosz, P. M. Moselund, P. D. Rasmussen, C. L. Thomsen and O. Bang 8. Continuous wave supercontinuum generation J. C. Travers 9. Theory of supercontinuum and interactions of solitons with dispersive waves D. V. Skryabin and A. V. Gorbach 10. Interaction of four-wave mixing and stimulated Raman scattering in optical fibers S. Coen, S. G. Murdoch and F. Vanholsbeeck 11. Nonlinear optics in emerging waveguides: revised fundamentals and implications S. V. Afshar, M. Turner and T. M. Monro 12. Supercontinuum generation in dispersion varying fibers G. Genty 13. Supercontinuum generation in chalcogenide glass waveguides Dong-Il Yeom, M. R. E. Lamont, B. Luther Davies and B. J. Eggleton 14. Supercontinuum generation for carrier-envelope phase stabilization of mode-locked lasers S. T. Cundiff 15. Biophotonics applications of supercontinuum generation C. Dunsby and P. M. W. French 16. Fiber sources of tailored supercontinuum in nonlinear microspectroscopy and imaging A. M. Zheltikov Index.

Tm-doped fiber laser mode-locked by graphene-polymer composite

We demonstrate mode-locking of a thulium-doped fiber laser operating at 1.94 μm, using a graphene-polymer based saturable absorber. The laser outputs 3.6 ps pulses, with ~0.4 nJ energy and an amplitude fluctuation ~0.5%, at 6.46 MHz. This is a simple, low-cost, stable and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.

Visible supercontinuum generation in photonic crystal fibers with a 400W continuous wave fiber laser

We demonstrate continuous wave supercontinuum generation extending to the visible spectral region by pumping photonic crystal fibers at 1.07 microm with a 400 W single mode, continuous wave, ytterbium fiber laser. The continuum spans over 1300 nm with average powers up to 50 W and spectral power densities over 50 mW/nm. Numerical modeling and understanding of the physical mechanisms has led us to identify the dominant contribution to the short wavelength extension to be trapping and scattering of dispersive waves by high energy solitons.

Watts-level frequency doubling of a narrow line linearly polarized Raman fiber laser to 589 nm

A single-mode, linearly polarized, 1118 nm ytterbium fiber laser was applied to pumping of a short fiber length, polarization-maintaining Raman cavity, resulting in a 0.4 nm linewidth, 23 W CW source at 1179 nm. Efficient, single-pass frequency doubling of the Raman source in MgO doped PPLN to 589 nm was demonstrated with CW power levels in excess of 3 W. No beam quality degradation was observed due to photorefraction at pump power densities up to 2 MW/cm(2). The proposed approach can be readily extended to Watt-level generation of any desired wavelength in the 560 to 770 nm range.

Continuous-wave, high-power, Raman continuum generation in holey fibers

The possibility of using low pump power for cw Raman continuum generation is demonstrated by optimization of the pump peak power and by accounting for the loss-related reduction of the effective length of Raman interaction in holey fibers. A 3.8-W, 324-nm-wide cw Raman continuum with a spectral power density higher than 10 mW/nm is generated in a completely fiber-integrated, single-mode format.

Nanosecond-pulse fiber lasers mode-locked with nanotubes

We demonstrate that mode-locking of ytterbium fiber lasers with a carbon nanotube saturable absorber can produce pulses ranging from 20 ps to 2 ns at repetition rates between 21 MHz and 177 kHz, respectively, depending on cavity length. Nonlinear polarization evolution is not responsible for mode-locking. Even in the nanosecond regime, clean single pulses are observed and the pulse train exhibits low jitter. Combined with extremely large chirp, these properties are suited for chirped-pulse amplification systems.

Comblike dispersion-profiled fiber for soliton pulse train generation.

A novel optical fiber [comblike dispersion-profiled fiber (CDPF)] that consists of a chain of alternating segments of standard telecommunication fiber and dispersion-shifted fiber is proposed for the generation of a soliton pulse train based on nonlinear transformation of an optical beat signal. A totally integrated all-optical fiber source of a 59.1-GHz train of 2.2-ps solitons is demonstrated with a CDPF. For a beat signal generator we use a dual-frequency erbium fiber laser incorporating fiber grating reflectors that provides 16-kHz linewidths and a low phase noise of optical beating (< 5 x 10(-5)). Significant suppression of stimulated Brillouin scattering, which is essential for this technique, is achieved in the CDPF.