A fiber disk laser is a

fiber laser A fiber laser (or fibre laser in British English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are rela ...

with transverse delivery of the

pump A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they ...

light. They are characterized by the pump beam not being parallel to the active core of the

optical fiber An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair Hair is a protein filament that grows ...

(as in a double-clad fiber), but directed to the coil of the fiber at an angle (usually, between 10 and 40 degrees). This allows use of the specific shape of the pump beam emitted by the

laser diode The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with ...

, providing the efficient use of the pump. Fiber disk lasers should not be confused with the

LaserDisc The LaserDisc (LD) is a home video format and the first commercial optical disc storage medium, initially licensed, sold and marketed as MCA DiscoVision (also known simply as "DiscoVision") in the United States in 1978. Its diameter typical ...

s (disk-shaped devices for storage and reading of information with laser beam) nor the

disk laser A disk laser or active mirror (Fig.1) is a type of diode pumped solid-state laser characterized by a heat sink and laser output that are realized on opposite sides of a thin layer of active gain medium. Despite their name, disk lasers do not hav ...

or "active mirror", which is a laser with a thin active layer where the heat sink is realized in a direction opposite to that of propagation of the output beam.

Realizations of fiber disk lasers

First disk lasers were developed in the

Institute for Laser Science The Institute for Laser Science is a department of the University of Electro Communications, located near Tokyo, Japan. History and achievements Established in 1980, the Institute specializes mainly in improving the performance of gas lasers, espe ...

, Japan. Several realizations of fiber disk lasers were reported. The fiber disk laser is so named because the fiber is tightly coiled. Typically, no special feedback for the laser frequency is required, as the small reflection at end of the fiber is sufficient to provide efficient operation. In this case, both ends of the coiled fiber can be used as output.

Application and power scaling

Fiber disk lasers are used for cutting of metal (up to few mm thick),

welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as b ...

and folding. The disk-shaped configuration allows efficient heat dissipation (usually, the disks are cooled with flowing water)); allowing power scaling. When the increase of the length of the fiber becomes limited by

stimulated scattering "Stimulated" (stylized as "$timulated") is a song by American rapper Tyga, and the fifth single from his mixtape '' Fuk Wat They Talkin Bout'' (2015). It was produced by Crakwav and uses a sample of " Children" by Robert Miles. The song is a respo ...

, additional power scaling can be achieved by combining several fiber disk lasers into a stack. The spiral-coiled configuration is not the only possible arrangement; any other scheme of stacking of optical fibers with lateral delivery of pump can also be called a fiber disk laser, even if the resulting shape of the device is not circular. The term ''fiber disk laser'' applies to the concept of lateral delivery of pump to the active optical fiber rather than specifically to a disk-shaped device. The optimal shape of the fiber disk laser may depend on the properties of the beam of pump available, as well as on the specific application.

References

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External links

* http://www.nature.com/nphoton/journal/vsample/nsample/full/nphoton.2006.6.html *http://ieeexplore.ieee.org/iel5/6572/17547/00811381.pdf *http://sciencelinks.jp/j-east/article/200705/000020070506A1021450.php Solid-state lasers Fiber optics