European company optimizes optical fiber for high-energy amplification

Dec. 1, 2005
Liekki, a supplier of highly doped optical fibers in Lohja, Finland, has developed an optical fiber for amplifying pulses from 1-micron lasers.

LOHJA, Finland - Liekki, a supplier of highly doped optical fibers in Lohja, Finland, has developed an optical fiber for amplifying pulses from 1-micron lasers.

The ytterbium-doped fiber product has a highly doped, large-mode-area fiber with very high cladding absorption. Typically this fiber is for lasers in applications related to targeting, range finding, remote chemical detection, and nonlinear frequency conversion for access to wavelengths from the infrared to the ultraviolet.

These applications require pulsed amplifiers with milli-Joule output energies and diffraction-limited beam quality, specifications that previously have been unattainable with fiber-based laser systems, company officials say.

Developing a fiber with a large mode area and short active fiber length was the breakthrough necessary to keep nonlinear effects to a minimum-the key limitation on the achievable output energy from conventional fiber amplifiers, company officials say.

“Overcoming this limitation will substantially increase the range of applications that can be addressed by fiber lasers,” says Mikko Soderlund, product manager of Liekki’s fiber products. “This highly doped ytterbium fiber with its extremely high pump absorption, high power-conversion efficiency, and large mode area is excellent for amplification of pulses with durations ranging from nanoseconds to femtoseconds.

“Such high-power pulses are typically used in material processing and micromachining,” Soderlund continues. The fiber features “a unique combination of a highly doped, 20-micron-diameter core, a large core-to-cladding ratio, and an efficient octagonal cladding shape.”

For more information contact Liekki online at www.liekki.com.

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