Optical Fiber Coupling System for Steerable Endoscopic Instruments.

In this paper, we present an optical coupling system that couples light from an Endostat fiber in a commercial laser surgical system into a smaller multimode fiber, in order to enable endoscopic probe steering in a tightly confined space. Unlike the Endostat fibers, which have a minimum bending radius of 12 mm due to the large diameter, our work allows the laser to be delivered by smaller fibers that can be readily bent at a 6-mm bending radius by a distal steerable mechanism. Such a readily achievable sharp bending facilitates the surgical laser to access hard-to-reach anatomies. We experimentally achieved an optical power coupling efficiency of ≈ 50%. Tissue ablation experiments were performed to prove the feasibility and potential of our light coupling system in clinical laser surgeries, as well as other optical fiber-based endoscopic medical devices.Clinical Relevance- Optical fibers are commonly used in laser-based surgical systems. The optical coupling system in this paper enables the laser to be delivered by small fibers, helps realize the fiber bending and steering, and hence allows the laser treatments of previous inaccessible anatomies.