Swept source optical coherence tomography with external clocking using voltage controlled oscillator

摘要

In this study, a beat signal recalibration method was developed for optical coherence tomography (OCT) with a high-speed wavelength-swept source. By adopting a voltage-controlled oscillator (VCO) mod-ulated by a sinusoidal waveform as a trigger for the OCT system, the broadening of the beat frequency due to laser tuning rate variations was recalibrated. For this study, OCT based on a Fourier domain mode-locked (FDML) laser at a sweep rate of 60.9 kHz was demonstrated. OCT im-ages of 1500×409 pixels were obtained with the sensitivity of 100 dB. Temporal frequency variations in the FDML laser and OCT images ob-tained with the proposed technique were also described. When compared to a conventional recalibration method using optical components, swept source optical coherence tomography operated with a VCO clock ex-hibited superior performance and high stability. From the experimental results, it was demonstrated that the proposed method is sufficient to re-calibrate the time-frequency variations in interferometry with a high-speed wavelength-swept source.