Crystal Fibre A/S Wins Circle of Excellence Award

Crystal Fibre A/S of Birker/od, Denmark, designed its AIR-12-1060 air-guiding fiber to transmit around the Nd:YAG wavelength of 1060 nm. The fiber, which uses the photonic bandgap principle to trap light in the hollow core, guides the major part of light in the air core and <2 percent in the silica glass material, significantly increasing the nonlinear and material damage thresholds. Fiber loss is 40 dB/km at peak transmission of 1060 nm, and below 100 dB/km in the range from 980 to 1080 nm; outside this range, the fiber is antiguiding.

The core diameter is 12 µm, but the fiber can transmit power levels corresponding to standard fibers orders of magnitude larger. The mode profile is close to a perfect Gaussian, and the fiber is bend-insensitive. It can be wound around a 1-cm-diameter mandrel without introducing further loss, and Fresnel reflections can be avoided when the fiber is used with "open" ends.

The hollow core of the fiber can be filled with gases, particles or liquids to create a long, intense interaction length between light and matter; for example, filling an air-core fiber with a highly nonlinear gas could provide a highly nonlinear fiber device.

The new fiber, which is available in lengths up to several hundred meters, could be used in research, biotechnology, materials processing and military applications. The sharing of expensive CW or pulsed lasers also is made easier with the air-guiding fiber.