Quality limiting factors of imaging endoscopes based on optical fiber bundles

Abstract

Nowadays, imaging endoscopes have a key role in medicine, for diagnostic, treatment and surgical applications. Coherent optical fiber bundles used for medical imaging show flexibility and a high active area, but they entail two main quality-limiting factors: leaky modes and crosstalk or interference between the optical fibers of the bundle. The former provokes a worsening of lateral resolution, while the latter causes a decrease in the contrast of the final image. In this work, both factors are studied in detail. We analyse the main characteristics of these effects, showing the limitations they impose to the endoscopic system. Finally, some solutions are proposed, and a method for determining optical fibers with the appropriate opto-geometrical parameters is presented in order to achieve an optimum design and improve the image quality of the endoscope.