时域光学相干层析系统噪音分析和实验研究

本文从理论和实验上分析了存在拍频噪音时时域光学相干层析系统的噪音特性,给出了拍频噪音的具体估算方法.建立了描述一般时域光学相干层析系统实际噪音的简化模型,并给出了测量和寻找平衡探测光学相干层析系统最佳工作状态的方法.理论计算表明,平衡探测光学相干层析系统的信噪比受限于拍频噪音,理想情况下,最大信噪比可达100 dB左右|同时实验表明,如果实际的系统不能完全消除冗余噪音,其信噪比可能要比理论值小10~20 dB.本文的主要结果将可直接用于时域光学相干层析系统工作状态的测试和诊断当中,对频域光学相干层析系统噪音性能的分析和优化也将有所裨益.

Noise Analysis and Experimental Study of Time Domain Optical Coherence Tomography

The effect of beat noise in a time domain optical coherence tomography (OCT) system was investigated through theoretical analysis and their comparision with experimental data.It is shown that the best SNR of a fiber-based and balanced OCT system is about 100 dB,being restricted by the beat noise.And,the excess intensity noise may not be eliminated completely in a practical balanced OCT system,and this leads to a SNR value of 10~20 dB lower than the theoretically expected value.A simplified physical model that describes the overall noise of a time domain OCT system was established.By using such a model,the influence of the optical interferemeter,signal filtering and amplifier circuits,the resolution of data acquisition system and the external electromegnetic interference source were analyzed on the overall signal-to-noise raitio of a practical optical coherence tomographic system,presenting a useful method to optimize the performance of the interested OCT system.