We have fabricated bandpass filters based on pi-shifted long-period gratings for application in actively mode-locked erbium fiber lasers. Introducing the pi-phase shift in the middle of the grating opens a bandpass within the core-cladding mode resonance peaks. With a 22-nm bandwidth filter inserted in an actively mode-locked erbium fiber sigma laser, solitonlike pulses are generated, with a po...

ii 1 Overview 1.1 Motivation ............................................................................1 1.2 The Challenge ........................................................................2 2 Background 2.1 Two-dimensional Photonic Crystal ................................................3 2.2 Two-dimensional Photonic Crystal Laser Cavity ................................6 3 Design and A...

High-speed laser cladding technology can significantly improve the efficiency of coating preparation and effectively widen application range cladding. In this study, Ni45 powders were deposited on steel substrate by traditional low speed high-speed process, respectively. The efficiency, surface forming, cross-sectional microstructure, microhardness, wear corrosion resistance properties cladded ...

We report the influence of higher order modes (HOMs) in large mode fibers operation in Q-switched oscillator configurations at ~2 μm wavelength. S(2) measurements confirm guiding of LP(11) and LP(02) fiber modes in a large mode area (LMA) step-index fiber, whereas a prototype photonic crystal fiber (PCF) provides nearly single-mode performance with a small portion of light in the LP(11) mode. T...

This paper summarizes the state of the art of direct metal laser-sintering (DMLS) in 2004, put into perspective by a review of its history from its roots in the 1970s, and discusses the trends going into the future. Since the 1970s, DMLS has evolved from an idea to a powerful commercial technology. The "family tree" of DMLS is explained with reference to related methods such as laser-cladding, ...

Here we report a compact monolithic 2000nm pulsed laser with a single spatial mode output, ~1.5ns pulse duration, 8kW peak power and >200mW average power at 20 kHz repetition rate. The gain-switched laser, consisting of a pair of fiber Bragg gratings and 0.5m of thulium-doped single cladding fiber, was core pumped by a high peak power pulsed 1.5 m laser. When the input pulse energy of the 20 kH...

We report the demonstration of the first, to our knowledge, cladding-pumped continuous-wave Yb(3+)-doped phosphate-glass fiber laser. Phosphate hosts are of interest because they can be much more heavily doped than silica, and because of the possibility that they may have a higher photodarkening threshold. In an 84.6 cm double-clad fiber doped with 12 wt. % of Yb(2)O(3) and laser-diode pumped a...

We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode with a Mode-Field-Diameter (MFD) of 59μm. We further demonstrate high pulse energy Second-Harmonic-Generati...

The benefits of the integration of novel optofluidic elements, e.g., fluidic lenses and liquid-core / liquid-cladding (L2) waveguides, for on-chip optical sample analysis are discussed. Using properly designed microfluidic channels, pre-calculated flow rate ratios and transparent fluids with different refractive indices but similar viscosity novel fluidic optical elements can be created. In thi...