Long-period gratings were fabricated in standard telecommunication fiber (Corning SMF-28) by use of what is believed to be record short-wavelength light from a 157-nm F(2) laser. Strong loss peaks were formed without the need for enhancement techniques such as hydrogen loading. The magnitude of the attenuation peak was sensitive to the single-pulse laser fluence, decreasing with increasing puls...

A microhole array in a common single-mode fiber is fabricated by selective chemical etching of femtosecond-laser-induced fiber Bragg grating (FBG), which has a laser-modified region extending from the fiber core to the cladding-air boundary due to laser self-focusing. The shape and size of the orderly microhole on the fiber surface are controlled via changing conditions of FBG fabrication and c...

We describe novel fiber Raman lasers pumped directly by spectrally combined high power multimode laser diodes at ∼975 nm and emitting at ∼1019 nm. With a commercial multimode graded-index fiber, we reached 20 W of laser output power with a record slope efficiency of 80%. With an in-house double-clad fiber, the beam quality improved to M = 1.9, albeit with lower output power and slope efficiency...

The paper reviews the recent progress on CO2-laser writing of long-period fiber gratings (LPFGs) in different kinds of fibers, including conventional single-mode fiber (SMF), boron-doped SMF, polarization-maintaining fiber, photonic crystal fiber, and polarization-maintaining photonic crystal fiber. In particular, we report the writing dynamics for the understanding of the physical mechanisms i...

Laser cladding is widely used for feature repair and manufacturing of large structural components. However, due to processing parameters thus energy densities variation, defects can form in laser clad materials. There a need understand the relationship between quality. This study therefore investigates critical producing Stellite® 21 (Co-Cr-MoNiC) alloy by cladding. Compared with conventional m...

This report summarizes the principal research activities in the Michigan Ion Beam Laboratory during the past calendar year. Fifty-six researchers conducted thirty-one projects at MIBL that accounted for over 3200 hours of equipment usage. The programs included participation from researchers at the University, corporate research laboratories, private companies, government laboratories, and other...