提出了一种提高扫频光学相干层析成像(SSOCT)系统灵敏度的方法。在SSOCT系统中, 当平衡探测器前耦合器的分束比不是50%∶50%时, 会在探测的干涉信号中引入直流偏置, 从而影响系统的灵敏度。分析了干涉信号中引入直流偏置时耦合器分束比对系统灵敏度的影响, 证明了通过调节耦合器的分束比并增加参考臂能量的方法可以提高系统的灵敏度。基于实验中SSOCT系统各器件的参数, 对系统的灵敏度进行了数值模拟, 模拟结果证明了所提方法的有效性, 灵敏度测试实验结果表明应用所提方法后系统的灵敏度提高了2.3 dB。

A method to improve the sensitivity of swept source optical coherence tomography (SSOCT) system is proposed. In the SSOCT system, when the splitting ratio of the coupler before the balanced detector, is not 50%∶50%, the DC bias in the detected interference signal will affect the sensitivity of the system. In this study, the influence of the splitting ratio of the coupler on the sensitivity is theoretically analyzed when the DC bias is introduced into interference signal, and it is proved that the sensitivity can be improved by the method of adjusting the splitting ratio and increasing the reference arm′s energy. Based on the parameters of the devices of the SSOCT system in the experiment, the sensitivity of the system is numerically simulated. The numerical simulation results prove the effectiveness of the proposed method, and the experimental results show that the sensitivity is improved by 2.3 dB after the proposed method is applied.