Nonlinear transmission and colour-centre dynamics in germanosilicate fibres at 420-540 nm

We report evidence in support of the view that induced loss and non-linear transmission in pure germanosilicate fibers at blue/green wavelengths are governed by the formation (via two-photon absorption), spontaneous and stimulated transformation and bleaching (via single-photon events) of Ge(1), Ge(2) and Ge(3) colour-centres. Using a tunable pulsed dye laser, the excitation spectrum of the induced absorption, its spectral attenuation and the effects of germania concentration and thermal annealing are investigated

Comparative measurement of Rayleigh scattering in single-mode optical fibers based on an OTDR technique

A new technique for comparing the Rayleigh scattering coefficients of single-mode step index fibers is described and its theoretical limitations are discussed. The validity of the technique is proven using telecommunications-grade fibers. Of particular interest is the variation of scatter found with increasing core index. In addition, the influence of small ( <0.1 percent) quantities of rare-earth dopant ions on the fiber scatter losses is analyzed for the first time

Broad-area diode-pumped 1W femtosecond fiber system

Summary form only given. High-average-power 310-fs pulses were obtained with an all-fiber chirped pulse amplification (CPA) system. Both the oscillator and the power amplifier are based on Er/Yb-doped fiber for cladding-pumping with broad-area laser diodes. A single 10-cm-long fiber grating is employed in the CPA system as a compact femtosecond-pulse stretcher/compressor

Regenerative Nd-glass amplifier seeded with a Nd fibre laser

Wavelength tuning and broad-bandwidth operation of a passively mode-locked Nd:fiber laser is demonstrated at 1060 nm. The oscillator pulses are used to seed a bulk regenerative Nd:glass amplifier, and 300-fs transform-limited pulses with an energy of 10µJ are obtained after 31 round trips at a repetition rate of 500 Hz

A diode-laser-pumped, Er³⁺-doped fibre laser operating at 1.57µm

Erbium-doped fibers show promise as stable narrow-linewidth laser sources and optical amplifiers operating in the third telecommunications window around 1.55µm Diode laser pumping is possible using the weak pump-band located at 807nm, although this band suffers severely from excited-state absorption (ESA), which reduces gain and pump efficiency. At the low pump power available from diode lasers the Er3+ behaves as a quasi four-level system. However, by codoping the core glass heavily with Yb3+, it is possible to excite the Er3+ ions indirectly using energy transfer. The Yb3+ provides an intense broad pump-band centered at 900nm, which reduces the effect of ESA. As a consequence of the resulting higher pump efficiency, the laser will oscillate at the required shorter wavelengths

Cladding pumped erbium fibre amplifier generating femtosecond pulses with an average power of 0.26W

Femtosecond pulse amplification in a cladding pumped fiber amplifier is demonstrated for the first time. A cladding-pumped Er3+ doped fiber amplifier generates 380fsec near-bandwidth-limited pulses at repetition rates up to 50MHz with an average power up to 0.26.

Generation of permanent optically-induced 2nd order nonlinearities in optical fibres by poling

It is shown that large permanent enhancements in second-order optical nonlinearity can be induced in germanosilicate fibers (both pure and co-doped with P) by application of a transverse dc electric poling field in the presence of high intensity light. The macroscopic inversion symmetry of the core material is broken by the excitation and alignment of defect centers. Significant frequency doubling results despite the absence of phase-matching. The saturation (both with increasing dc-field and intensity) of this effect is investigated

Diode-pumped high-average power femtosecond fiber laser systems

The recent progress in femtosecond laser technology is currently driven by the prospect of fully diode pumped systems, which promise the eventual replacement of the well-established Ti:sapphire laser in the field of ultrafast optics. Apart from more traditional diode-pumped solid-state lasers, fiber-based systems have received an increasing amount of attention due to the uniquely compact assemblies possible with fiber lasers. However, to date fiber lasers have replaced Ti:sapphire-based systems only in areas, were low power levels are required, such as the injection seeding of regenerative amplifiers. Here, we show that fiber lasers can also produce power levels and pulse widths that are sufficient for the pumping of optical parametric oscillators (OPOs) and amplifiers (OPAs)

Midinfrared frequency combs from coherent supercontinuum in chalcogenide and optical parametric oscillation

International audienceWe observe the coherence of the supercontinuum generated in a nanospike chalcogenide-silica hybrid waveguide pumped at 2 mu m. The supercontinuum is shown to be coherent with the pump by interfering it with a doubly resonant optical parametric oscillator (OPO) that is itself coherent with the shared pump laser. This enables coherent locking of the OPO to the optically referenced pump frequency comb, resulting in a composite frequency comb with wavelengths from 1 to 6 mu m. (C) 2014 Optical Society of Americ