A schematic of the employed FD-OCT imaging system is illustrated in Fig. 1. Light coming from the source [SLD Broadlighter S840, Superlum (County Cork, Ireland) output power of , centre wavelength at , full spectral width at half maximum of ] is split by the directional coupler into the sample arm and the reference arm. The interference of backscattered light returning from both arms is measured by a spectrometer equipped with a silicon linear charge coupled device (CCD) camera [Atmel (San Jose, California) AVIIVA M2, , each wide]. In our custom spectrometer design we used a focal length achromatic collimating lens (MO3), a transmission diffraction grating (Wasatch Photonics, Logan, Utah), and a focal length achromatic lens (L3). Data from the linear CCD was transferred to a PC via a Cameralink cable and a high speed PCI frame grabber [National Instruments (Austin, Texas) NI-1430]. Residual dispersion of the system caused by MO1, L1, L2, and the optical fiber mismatch has been compensated for by using a dispersion compensating block (DCB) containing a pair of lenses L1 and L2, and a -thick BK7 slide.