Homodyne en face optical coherence tomography

We demonstrate, for what we believe to be the first time, the use of a 3×3 fiber-optic coupler to realize a homodyne optical coherence tomography (OCT) system for en face imaging of highly scattering tissues and turbid media. The homodyne OCT setup exploits the inherent phase shifts between different output ports of a 3×3 fiber-optic coupler to extract amplitude information of a sample. Our homodyne en face OCT system features a measured resolution of 14 μm axially and 9.4 μm laterally with a 90 dB signal-to-noise ratio at 10 μs integration time. En face OCT imaging of a stage 52 Xenopus laevis was successfully demonstrated at a depth of 600 μm within the sample.