New fiber overcomes photo-darkening for UV, blue, and green light transmission in bio, medical apps
JANUARY 26, 2009--Fibercore Ltd. (Southampton, England) is targeting high-power medical and biotechnical applications with the launch of its SM300 single-mode fiber at this week's Photonics West exhibition (January 24 - 29). The SM300 is designed for applications such as such as laser Doppler velocimetry (LDV), laser Doppler anenometry (LDA), holography, two-photon spectroscopy, and others requiring a single mode and/or high beam quality to be delivered in ultraviolet, blue, or green wavelengths (300 nm to 560 nm).
Fibercore's new offering addresses the problem of photo-darkening in conventional fibers when transmitting more than a few milliwatts in the ultraviolet, blue, or green portions of the spectrum. The SM300 fiber uses an un-doped silica core with a fluorinated silica cladding rather than a conventional germanium-doped silica core. The advantage of this is that with the vast majority of the power traveling in pure silica, the generation of germania defects that have been so damaging to transmission is no longer an issue. With a cutoff wavelength below 300 nm, the long-wavelength portion of the ultraviolet spectrum is also accessible.
Furthermore, the numerical aperture is relatively low; typically between 0.1 and 0.11, maximizing the model area, minimizing the power density, and increasing the non-linear threshold. This is important in addressing nonlinear, typically Brillouin, scattering.
"SM300 is the first in a planned range of fibers that will include both single mode and polarisation maintaining variants, covering those wavelengths most at risk from photo-darkening between 300 and 532 nm" said Dr Chris Emslie, Managing Director of Fibercore. "Its characteristics enable customers to achieve results that would not be possible from fibers currently available on the market." Fibercore Ltd. is a developer and manufacturer of specialty optical fibers and a U.K.-based subsidiary of Cisco Systems.
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Fibercore Ltd.
Posted by Barbara G. Goode, [email protected].