Type I fiber Bragg gratings (FBG) written through the coating of various off-the-shelf silica fibers with a femtosecond laser and the phase-mask technique are reported. Inscription through most of the common coating compositions (acrylate, silicone and polyimide) is reported as well as writing through the polyimide coating of various fiber cladding diameters, down to 50 µm. The long term anneal...

This letter reports a multiplexed optical displacement sensor using a thin core fiber (TCF) exciter. The TCF exciter is followed by a stripped single mode optical fiber. A small section of buffer is used as the movable component along the single mode fiber. Ultra-weak cladding mode reflection (< - 75 dB) was employed to probe the refractive index discontinuity between the air and buffer coating...

New dual temperature and strain sensor has been designed using eccentric second-order fiber Bragg gratings produced in standard single-mode optical fiber by point-by-point direct writing technique with tight focusing of 800 nm femtosecond laser pulses. With thin gold coating at the grating location, we experimentally show that such gratings exhibit a transmitted amplitude spectrum composed by t...

Laser cladding, a novel surface treatment technology, utilizes high-energy laser beam to melt diverse alloy compositions and form specialized alloy-cladding layer on the of substrate enhance its property. However, it can generate substantial residual stresses during rapid cooling heating stages, due inadequate selection cladding process parameters disparities in thermophysical properties betwee...

Cr5Mo steel with high thermal strength is frequently applied as the material for hydrocracking furnace tubes. Nonetheless, tubes are prone to failure in a high-temperature environment, threatening production safety. Considering that IN718 nickel-base superalloy has favorable oxidation resistance, coating was fabricated on substrate through laser cladding. The effect of process parameters resist...