Complex conjugate removal in ss optical coherence tomography

The development of Fourier Domain OCT (FDOCT) systems significantly improved sensitivity and imaging speed and catalyzed the commercialization of OCT technology. However, the transition from time-domain to Fourier domain was not without cost. The complex conjugate ambiguity is a non-trivial artifact resulting from direct Fourier detection in FDOCT. While most FDOCT systems avoid this artifact by limiting their axial imaging range, complex conjugate removal (CCR) in swept-source OCT (SSOCT) seeks to suppress or eliminate the complex conjugate ambiguity. CCR for SSOCT, either by phase-shifting, heterodyning, or optical demodulation, increases the axial imaging range by a factor of 2 compared to conventional FDOCT. This technological development is important in many OCT applications, including ophthalmology since the increased imaging depth is necessary to visualize the entire anterior segment of the human eye.