A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.

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CODATA Recommended Values of the Fundamental Physical Constants: 2006

The rise in output power from rare-earth-doped fiber sources over the past decade, via the use of cladding-pumped fiber architectures, has been dramatic, leading to a range of fiber-based devices with outstanding performance in terms of output power, beam quality, overall efficiency, and flexibility with regard to operating wavelength and radiation format. This success in the high-power arena is largely due to the fiber’s geometry, which provides considerable resilience to the effects of heat generation in the core, and facilitates efficient conversion from relatively low-brightness diode pump radiation to high-brightness laser output. In this paper we review the current state of the art in terms of continuous-wave and pulsed performance of ytterbium-doped fiber lasers, the current fiber gain medium of choice, and by far the most developed in terms of high-power performance. We then review the current status and challenges of extending the technology to other rare-earth dopants and associated wavelengths of operation. Throughout we identify the key factors currently limiting fiber laser performance in different operating regimes—in particular thermal management, optical nonlinearity, and damage. Finally, we speculate as to the likely developments in pump laser technology, fiber design and fabrication, architectural approaches, and functionality that lie ahead in the coming decade and the implications they have on fiber laser performance and industrial/scientific adoption.

High power fiber lasers: current status and future perspectives [Invited]

The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed

Photonic-Crystal Fibers

A review on the latest developments on graphene, written from the perspective of a chemist, is presented. The role of chemistry in bringing graphene research to the next level is discussed.

The chemistry of graphene

1907 nm generation by pure vibrational stimulated Raman scattering in hydrogen-filled hollow-core fiber is demonstrated. Due to special design of hollow-core revolver fiber with nested capillaries, the Raman threshold as low as 270 W of peak power is achieved.

Low-threshold 1064 to 1907 nm hydrogen Raman laser based on hollow-core fiber

Fluorescence properties of a Ce3+-doped silica fiber at different pump wavelengths between 405nm to 450 nm are investigated. With 405 nm pump wavelength and a fiber length of ∼130-140 cm broadband fluorescence of ∼280nm is achieved.

Fluorescence bandwidth of 280nm from broadband Ce 3+ –doped silica fiber pumped with blue laser diode

A germanium-doped silica-core fiber with an active region in the form of a thin ring of silica doped with
bismuth ions was fabricated. Bismuth doping in the ring surrounding the core allows to stabilize bismuth in silica glass,
and it does not impose any restrictions on the composition of the core. The bismuth concentration in the ring is less than
0.2 wt.%. The GeO2 concentration in the core is more than 15 mol.%. A high germanium concentration in the core allows
to shift the zero dispersion wavelength to 1860 nm and to obtain a high nonlinear refractive index (n2 more than 3,2*10-20
m2/W). Spectroscopic investigations were carried out in the visible and near infrared (800-1700 nm) spectral range.
Despite the small concentration of bismuth, we observed the absorption and luminescence characteristic bands,
confirming the presence of bismuth active centers in silica glass. Upon pumping at 1350 nm the on/off gain spectrum
was measured on a 20-m fiber. The gain was observed throughout investigated range of 1430-1530 nm. The maximal
gain of ~9.5 dB was obtained near 1430 nm. The results of the spectroscopic investigations of the fiber with a thin active
Bi-doped ring showed prospects of the creation and application of such fiber type for laser and nonlinear optics.

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Spectroscopic investigations of dispersion-shifted fiber with thin active Bi-doped ring and high nonlinear refractive index

Improvements, in terms of output power, spatial beam quality, bend insensitivity … are still required in the field of single-mode fiber lasers. A major trend is to increase the active core area to increase the thresholds of nonlinear effects while ensuring a transverse single-mode behavior. Actually, increasing the active ions' concentration is also demanded since it allows a drastic reduction of the fiber length, everything being equal. Two non-exclusive strategies are laid out to overcome fiber laser limitations. On the one hand, a large mode area photonic bandgap fiber is shown to lead to a transverse single-mode fiber laser with very good lasing efficiency. On the other hand, it is demonstrated that surrounding a highly multimode active core by a properly designed microstructured cladding allows the fiber laser to be operated in the single-mode regime.

Large Mode Area All-Solid Optical Fiber Lasers with Tailored Microstructured Cladding

We  report  on  thulium-doped  all-fiber  lasers  based on the nonlinear amplifying loop mirror and mode-locked by both a semiconductor saturable absorber (SESAM) and  single-walled  carbon  nanotubes (SWCNT).  An  intracavity  and  external dispersion management was realized with the aid of a passive germanium-silicate fiber.  SESAM  mode-locked laser  generates  as  short  as  230-fs  pulses with maximum  average  output  power  of  106 mW, corresponding to a 3.7 kW peak power and almost 2 nJ  pulse  energy.  In  contrast  to  SESAM-based laser,  the SWCNT  mode-locked  laser  generates 450-fs  pulses  of  mW-level  average  output power respectively.

E. M. Dianov

Papers

Low-threshold 1064 to 1907 nm hydrogen Raman laser based on hollow-core fiber

Fluorescence bandwidth of 280nm from broadband Ce 3+ –doped silica fiber pumped with blue laser diode

Spectroscopic investigations of dispersion-shifted fiber with thin active Bi-doped ring and high nonlinear refractive index

Large Mode Area All-Solid Optical Fiber Lasers with Tailored Microstructured Cladding

All-Fiber Thulium-Doped Mode-Locked Lasers Based on the Nonlinear Amplifying Loop Mirror