Spectral OCT (SOCT), with high acquisition speed and high dynamic range, has been implemented by many research
groups in the world. However, SOCT image inherently has virtual image, including auto-correlation noise and mirror
image. The existence of the virtual image may deteriorate the quality of the image. In order to eliminate those virtual
images, some methods have been demonstrated effective, such as differential SOCT and complex SOCT. In this paper, a
novel method is proposed i.e. three-phase shifting method. The pathlength of the reference arm is changed for certain
distance by PZT controller. Three phase shifted coherence spectra are recorded for A-line. The reconstruction algorithm
can eliminate both auto-correlation noise and minor image, thus improve the signal-to-noise ratio of the SOCT image.
Furthermore, this method is also able to amplify the measuring range of SOCT by a factor of 2. An intact porcine cornea
tissue in vitro is further used to show the potential of this method for high-resolution biological imaging.