Bright light from glass wires
Fiber lasers were first proposed more than 40 years ago, and from the beginning they were attractive for obvious reasons. Coating the ends of the fiber forms a completely sealed resonator immune to misalignment and contamination, more similar in this regard to some gas lasers than to other types of solid-state lasers.
Piggybacking on the success of EDFAs for telecom, recent developments in fiber lasers have positioned this technology to compete with conventional solid-state lasers in many applications.
An important decision in a system design is often whether and when off-the-shelf-optics are more appropriate than custom optics.