We developed an ultra high resolution Fourier-Domain-OCT (FD-OCT) system for the use in dermatology. An axial resolution of less than 3 μm within the tissue was achieved by superimposing two broadband SLDs. FDOCT systems offer new possibilities for the design of the interferometer and the application system. Since no phase modulator is needed, the reference plane can be realized within the application system. This leads to a substantial improvement in the sensitivity against polarisation mode dispersion (PMD). It furthermore makes an elaborate chromatic dispersion matching obsolete. Two different applicaton system were compared. In the first system the reference wave was created by a plane plate just a few 100 μm above the probe. In the second approach an extra beam splitter and a mirror to generate the reference wave was used.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.