A fiber laser is a solid-state laser in which the active medium is an optical fiber doped with rare-earth ions. When an external energy source, such as a pump diode, is applied to the fiber, it excites the rare-earth ions and causes them to emit photons. These photons bounce back and forth within the fiber, creating a highly concentrated beam of light. This beam is then amplified as it passes through additional doped fibers or other optical components. The particular wavelength (1064nm) and other unique properties of fiber lasers make them ideal for a variety of industrial, medical, and scientific applications, including cutting, welding, and drilling materials, as well as for use in telecommunications and spectroscopy. Sometimes you will hear the terms Q-Switched laser or MOPA (Master Oscillator power Amplifier) used to describe fiber lasers. Q-Switched lasers have fixed pulse widths and cost less than MOPA sources that have wider frequency range and variable pulse width for more marking control and precision.