Comparison of micro-optic systems for close-focus microendoscopic applications

To detect disease in organs with small lumens like the pancreas or fallopian tubes, where lumens may be collapsed or filled with mucus, cilia, or plicae, minimally invasive submillimeter endoscopes must meet unique optical requirements. They must provide a moderate angular field of view (AFOV), a close working distance (WD), and provide adequate resolution for the application. Additionally, when using miniature fiber bundles for image relay, the effect of the honeycomb pattern and potential fiber crosstalk must be considered. We compare the optical performance of a gradient refractive index (GRIN) singlet, a 3D-printed doublet, and a 3D-printed triplet, as well as discuss the consequences of fiber bundle use. We show that for our designs, both GRIN lenses and 3D printed aspheric lens systems can meet our application requirements, with to the ability to resolve less than 10μm at 10% contrast. The effect of fiber bundle crosstalk is shown to be negligible because of limited mode coupling in realistic manufactured fiber bundles.