INSTITUTE OF APPLIED PHYSICS - Fiber-Optic Frequency Conversion

Fiber-Optic Frequency Conversion

Yb-doped fiber lasers have become very stable and efficient high-power laser sources. However, there are many important applications that require wavelengths outside of the amplification band of Ytterbium (and in many cases wavelengths that cannot be obtained with conventional laser transitions). Some of these applications include new medical treatments, spectroscopy, environmental sensing, or laser displays. Bringing the benefits of fiber lasers into these applications would spur the development of those fields. This can be achieved by exploiting non-linear frequency conversion, in which the light emitted by a fiber laser is transformed into one or more widely separated wavelengths. Typically this is carried out using a nonlinear element such as a crystal or an optical fiber.

In the Fiber and Waveguide Lasers Group we have developed considerable Know-How in the efficient frequency conversion of fiber lasers. Thus, we have already demonstrated high-average-power sources with an excellent beam quality in the green and in the red spectral range or octave-spanning supercontinuum sources. Furthermore, we have developed a very versatile multi-wavelength source for Coherent anti-Stokes Raman scattering (CARS) microscopy.

For example, one effect of current research activity in our group is the exploitation of degenerated four-wave mixing in photonic-crystal fibers. By adjusting the dispersion properties of the fibers, different wavelengths in the visible and the mid-IR can be efficiently generated.

Selected publications:

[1] T. Schreiber, J. Limpert, H. Zellmer, A. Tünnermann, K.P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Optics Communications, Vol. 228, (2003)

[2] T. Schreiber, T. Andersen, D. Schimpf, J. Limpert, and A. Tünnermann, "Supercontinuum generation by femtosecond single and dual wavelength pumping in photonic crystal fibers with two zero dispersion wavelengths," Opt. Express 13, 9556-9569 (2005),link to journal

[3] D. Nodop, C. Jauregui, D. Schimpf, J. Limpert, and A. Tünnermann, "Efficient high-power generation of visible and mid-infrared light by degenerate four-wave-mixing in a large-mode-area photonic-crystal fiber," Opt. Lett. 34, 3499-3501 (2009), link to journal