Pre-welding analysis and associated fiber lasers utilizing pre-selected spectral bandwidths that avoid the spectrum of an electronic transition of a metal/alloy vapor

A narrowband fiber laser comprising:

• a. first and second fiber Bragg gratings pre-selected to emit an output in a pre-determined wavelength range and linewidth range, the narrow bandwidth linewidth range corresponding to a spectral bandwidth that avoids the spectrum of an electronic transition of metal/alloy vapor, wherein the predetermined wavelength range and linewidth range does not interfere with any spectral lines of the metal/alloy vapor having an oscillator strength value above the standard deviation of the range of oscillator strength values for spectral lines of the metal/alloy vapor, wherein a central wavelength of the predetermined wavelength range is in a range from 1400 nanometers (nm) to 2100 nm;
• b. an active fiber configured to suppress non-linearities disposed between the first and second fiber Bragg gratings;
• and
• c. one or more diode lasers configured to pump the active fiber so it can lase in the predetermined wavelength range and linewidth.