We report that the complex conjugate ambiguity in spectral domain OCT approaches (including swept source OCT and Fourier-domain OCT) may be removed by the use of novel interferometer designs based on N×N couplers. An interferometer based on a 3 × 3 truly fused fiber coupler with equal splitting ratios provides simultaneous access to components of the complex interferometric signal separated by 120°. These phase components may be converted to quadrature components by use of a simple trigonometric operation, and then inverse Fourier transformed to obtain A-scans and images free of complex conjugate artifact. We demonstrate instantaneous complex spectral-domain OCT using a novel Fourier-domain OCT system employing photodiode arrays, and will also report on a similar system design for instantaneous complex swept-source OCT.