共路径光相干成像系统光纤探头的研究

Probe of Common-path Optical Coherence Tomography

本文提出了基于楔形光纤以及端面成角度光纤的共路径光相干成像系统探头,实现背向散射信号在其端部的共路径相位干涉,从而获得待测件断面成像信息.首先,建立了共路径光相干成像系统光路及探头相位干涉的理论模型,分析了各光纤探头尺寸与干涉信号强度、系统性能的关系.其次,分别设计出楔形光纤、端面成角光纤探头,开展了共路径光路干涉实验,搭建了工作波长为1 550nm的共路径光路测试系统.然后,根据不同待测样品的散射率,设计并研制了不同角度的楔形光纤探头,分析了不同尺寸的光纤探头对系统性能的影响,针对不同样品开展了固定探头探测实验.实验结果表明,楔形光纤端部可直接对输出光聚焦,照射在被测样品上,且其端面成一定角度时,可调节输出分光比,实现对参考信号的调节,提高了系统信噪比.为进一步开展共路径光相干成像系统的研究奠定了基础.

A probe of the common-path optical coherence tomography（CP-OCT） is presented based on the wedge-shaped and angled fiber,which can achieve the phase interference for the backscatter signal,so that the cross-section imaging information of the sample under test can be obtained.Firstly,an optical path of the CP-OCT and its theoretical model of phase interference at the probe end are set up,and the relationship between probe size and interference strength is analyzed.Secondly,the optical fiber probe with the wedge-shaped end is designed,and the experiment system for the CP-OCT at the wavelength of 1550nm is built.And then,depended on the scattering rate of the sample,various probes with different angles are prepared and the system performance with different probes is analyzed.The experimental results show when the end of the probe is cut to a certain angle shape,the output splitting ratio can be adjusted to achieve the adjustment of the reference signal so that signal noise ratio can be improved.The research works lay the foundation for the establishment of the effective CP-OCT system.