Optimization of the Source Power Usage in Spectral-Domain Optical Coherence Tomography

Source power consumption and system sensitivity of a spectrometer-based optical coherence tomography (SD-OCT) system are investigated. Our study shows that the performance of an SD-OCT system can be classified into two categories based on the beam-splitting ratio
R
between the sample and reference rams in the Michelson interferometer. For the classic SD-OCT configuration,
R
is less than 1.0, and the improvement of the sample light collection efficiency through reducing
R
will increase the cost of OCT source power. We find that through combining the detection and source arms of a Michelson interferometer together with a fiber optic circulator and choosing a beam splitter with
R
> 1.0, OCT source power can be reduced greatly without losing the system sensitivity. Light squandered in the reference arm is minimized, and efficiencies of source power usage and sample light collection can be improved at the same time. Further analysis shows that the optimized signal-to-noise ratio of our approach is higher than that of the classic SD-OCT system. Measured sensitivity of our SD-OCT setup is 98.56 dB when the source power is 1.38 mW. Chicken trachea and heart are imaged successfully
in vitro.