ABSTRACT
Several types of OCTs have been developed and some of these are shown in Figure 8.2. They are often called time domain OCT (TD-OCT), frequency
domain OCT (FD-OCT), and swept source OCT (SS-OCT). TD-OCT is a method shown in Figure 8.2(a) and the interference pattern arises according to time delays of scattered light. In FD-OCT the interference pattern is detected as a spectrum using a grating and a charge-coupled device (CCD) detector, as shown in Figure 8.2(b). In this method it is not necessary to move the mirror of reference light. SS-OCT uses a swept laser source at a high-frequency scanning rate (typically few dozens of kHz), as shown in Figure 8.2(c). The advantage of this method is a high signal-to-noise signal.
