Fiber lasers are a type of solid-state laser that uses optical fibers doped with low amounts of rare-earth halides or ions (erbium, neodymium, ytterbium or praseodymium) as the lasing medium to amplify light. It can also refer to a laser where most of the laser resonator is made of fibers. They have high output power, good optical quality and are highly reliable with a long life span.
Fiber lasers are similar to gas lasers, but part of the fiber is actually used as the resonating cavity where the laser action takes place. They are compact because the fiber can be bent or coiled to save space, efficient and have good beam quality. The material processing, metal and polymer fabrication, telecommunications, spectroscopy, medical and optical communications industries all use fiber lasers. In medicine, fiber lasers are used to photo-activate light-sensitive drugs as well as other medical treatments.
They are components in high speed commuting, WDM systems and high-speed optical receivers. Fiber lasers are powerful and can cut through almost any metal or plastic resin material. Laser cutting, welding, folding, ablation, annealing, engraving, sintering, printing, scribing, marking and drilling can all be accomplished with the use of a fiber laser to produce jewelry, weapons, aerospace components and medical tools. They are also found within the semiconductor, electronics, automotive, food processing, packaging and general manufacturing industries.
Fiber lasers are composed of a laser system and flexible quartz or glass fibers that use TIR (total internal reflection) to pass light through thousands of reflections, and a diode which uses groups of mirrors to divide beams into sections along an axis to produce near-monochromatic light. Fiber lasers are able to emit several wavelengths at the same time. In order to do so, a pump light is launched from one side through a semi-transparent mirror into the core of the glass/quartz fiber.
This generates a laser light, which is extracted on the other side. Some fiber lasers are high powered, which require high pump intensities. This type of laser can be maintained over a long distance and can be active up to several kilometers. All fiber lasers are easily delivered to moveable focusing elements and offer high vibrational stability. The use of fiber optics instead of a hard optic resonator eliminates the high maintenance, contamination and alignment issues as seen with other types of lasers.