Liekki Introduces Optimized Fiber For High-Energy Amplification
Lohja - Liekki, the leading supplier of highly doped optical fibers, has developed an ideal fiber for amplifying pulses from 1 µm lasers.
Liekki expands its broad, ytterbium-doped fiber product family with a highly doped, large-mode-area fiber with very high cladding absorption (Yb1200-20/125DC). Typically this fiber is used in lasers for applications in materials processing (cutting, marking, drilling), targeting and 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 mJ output energies and diffraction-limited beam quality, specifications that have previously been unattainable with fiber-based laser systems. Development of a fiber with a large-mode-area and short active fiber length provided the breakthrough required to minimize nonlinear effects, the key limitation on the achievable output energy from conventional fiber amplifiers. "Overcoming this limitation will substantially increase the range of applications that can be addressed by fiber lasers," according to Mr. Mikko Söderlund, 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", continues Mr. Söderlund. The Yb1200-20/125DC fiber features a unique combination of a highly doped, 20 µm diameter core, a large core-to-cladding ratio, and an efficient octagonal cladding shape. These features result in a cladding pump absorption of 6.8dB/m at 920nm and up to 29dB/m pump absorption near the peak at 976nm, enabling use of very short active fiber lengths (few 10's of centimeters for 976nm pumping). Applications using this fiber benefit from high extractable energy and excellent beam quality. The use of standard 125 µm cladding diameter is another advantage, broadening the fiber's usability, for example, with standard telecom fiber stripping, splicing, and connectorization equipment.
Liekki supplies a passive fiber matched to the active ytterbium fiber, so that excellent beam quality is maintained throughout the monolithic fiber laser or amplifier assembly. Combiners, such as 6+1/1 based on tapered fiber bundle technology are also available through Liekki. "This approach is part of our mission to provide complete solutions to our customers", concludes Mr. William Willson, Liekki's Vice President Marketing and Sales.
SOURCE: Liekki Corporation