Characterization of UV single-mode and low-mode fibers

There is an increasing demand for UV single-mode fibers with long-term stability. Due to the small diameter, the coupling efficiency is extremely low, if broadband light-sources or LEDs with near field diameter in the order of approx. 500 μm are used. Therefore, UV lasers are the real candidates for these fibers. Although the power is in the order of several milliwatts, the intensity in the small fiber core is significantly high. Therefore, UV damage has to be taken into account, even in the wavelength region above 300 nm. After the introduction of adjusted measurement systems for these fibers, the properties of some low-mode and single-mode fibers will be shown and discussed.