Tunable spatiotemporal mode-locked fiber laser at 1.55 μm.

We report the spatiotemporal mode-locked multimode fiber laser operating at 1.55 µm based on semiconductor saturable absorber mirrors with the mode-locking threshold as low as 104 mW. Benefiting from the multimode interference filtering effect introduced in the laser cavity not only the central wavelength can be continuously tuned from 1557 nm to 1567 nm, but also the number of the output pulses can be adjusted from 1 to 4 by simply adjusting the polarization controllers.

2166 nm all-fiber short-pulsed Raman laser based on germania-core fiber.

We report a compact 2166 nm germania-fiber short-pulsed Raman laser based on the cavity matching scheme. The all-fiber Raman cavity is formed by a pair of 2166 nm fiber Bragg gratings. High-power noise-like pulses from a 1981 nm fiber laser are used to pump a 22 m germania-core fiber for providing Raman gain at ∼2166 nm, and readily realizes the Raman-cavity synchronization with high mismatching tolerance.

Compact all-fiber 2.1-2.7 m tunable Raman soliton source based on germania-core fiber.

Although ultrafast rare-earth-doped fiber lasers mode-locked at near-infrared and ∼3 m wavelengths have been well developed, it is relatively difficult to achieve ultrafast fiber laser emitting in the 2.1-2.7 m spectral gap between ∼2 m (Tm fiber) and ∼2.

Dissipative soliton resonance in Bismuth-doped fiber laser.

We experimentally demonstrate the generation of dissipative soliton resonance (DSR) in a passively mode-locked Bi-doped fiber ring laser based on nonlinear polarization rotation (NPR) technique. The DSR with the central wavelength of 1169.5 nm has a repetition rate of 343.

Identification of Nanocrystalline Inclusions in Bismuth-Doped Silica Fibers and Preforms.

The nature of nanocrystalline inclusions and dopant distribution in bismuth-doped silicate fibers and preforms are studied by scanning and transmission electron microscopy, and energy and wavelength-dispersive X-ray microanalysis. The core compositions are Bi:SiO2, Bi:Al2O3-SiO2, Bi:GeO2-SiO2, Bi:Al2O3-GeO2-SiO2, and Bi:P2O5-Al2O3-GeO2-SiO2. Nanocrystals of metallic Bi, Bi2O3, SiO2, GeO2, and Bi4(GeO4)3 are observed in these glasses.

Fabrication of Bragg gratings in microstructured and step index Bi-SiO2 optical fibers using an ArF laser.

An ArF excimer laser was used to fabricate Bragg gratings in fibers with Bi-SiO(2) core and microstructured or F-doped claddings without fiber presensitization. Average and modulated refractive index changes of 2.7 × 10(-4) and 1.

Mechanisms of optical losses in Bi:SiO2 glass fibers.

The mechanisms of optical losses in bismuth-doped silica glass (Bi:SiO(2)) and fibers were studied. It was found that in the fibers of this composition the up-conversion processes occur even at bismuth concentrations lower than 0.02 at.

Microfluorescence analysis of nanostructuring inhomogeneity in optical fibers with embedded gallium oxide nanocrystals.

A spectroscopic protocol is proposed to implement confocal microfluorescence imaging to the analysis of microinhomogeneity in the nanocrystallization of the core of fibers belonging to a new kind of broadband fiber amplifier based on glass with embedded nanocrystals. Nanocrystallization, crucial for achieving an adequate light emission efficiency of transition metal ions in these materials, has to be as homogeneous as possible in the fiber to assure optical amplification. This requirement calls for a sensitive method for monitoring nanostructuring in oxide glasses.

Photosensitivity and stress changes of Ge-free Bi-Al doped silica optical fibers under ArF excimer laser irradiation.

The photosensitivity of germanium free Bi-Al-doped silica fibers with different bismuth concentrations was investigated using ArF excimer laser radiation at 193 nm and fiber grating formation. For the fiber with the highest bismuth concentration maximum refractive index changes of 2.2 × 10(-3) and 2.

Fabrication and thermal decay of fiber Bragg gratings in pristine and H2-loaded Bi-Al co-doped optical fibers.

A cw-244-nm-Ar(+) laser was used to fabricate Bragg gratings in pristine and H(2)-loaded Bi-Al-SiO(2) optical fibers with index changes as high as 3.6 × 10(-4) and 19.3 × 10(-4), respectively.

Influence of electron irradiation on optical properties of Bismuth doped silica fibers.

We report a study of the attenuation spectra transformations for a series of Bismuth (Bi) doped silica fibers with various contents of emission-active Bi centers, which arise as the result of irradiation by a beam of high-energy electrons. The experimental data reveal a substantial decrease of concentration of the Bi centers, associated with the presence of Germanium in silica glass, at increasing the irradiation dose (the resonant-absorption bleaching effect in germano-silicate fiber). In contrast, the spectral changes that appear in Bi doped alumino-silicate fiber have through irradiation a completely different character, viz.