Plug-and-play endoscopic OCT enabled by a fully fiber-integrated 3D-printed probe

Abstract

Endoscopic optical coherence tomography (OCT) brings depth-resolved imaging into small lumens and confined spaces, but each probe must be assembled from spliced, cleaved, and aligned components, and each exchange requires renewed matching of the reference arm. Common-path probes remove the matching step, yet their reference is inherited from a fixed interface and cannot be designed independently. Here we present a fully fiber-integrated OCT (F2I-OCT) probe in which a single two-photon-polymerized element defines, for the first time, the complete distal interferometric architecture. This novel architecture integrates beam expansion, side-view redirection, focusing, and a common-path reference within one printed micro-optical body while remaining independently designable. Probe fabrication reduces to a print-and-bond process, and probes exchange in a plug-and-play manner on an unmodified OCT system. Twenty consecutively assembled probes showed a returned-reference-power standard deviation below 0.15 dB, probes carrying three different objective designs were exchanged without any interferometer adjustment, and the probes achieved above 93 dB sensitivity, resolving layered structures in ex vivo airway and dental pulp cavity samples. Printing the interferometer rather than a standalone micro-lens lowers both the fabrication and the operation barriers of endoscopic OCT, establishing a route to batch-produced, application-specific probes for clinical screening, single-use intervention, neurotechnology, and confined-space inspection.