Interferometric method for in-situ monitoring of fiber insertion in 2D fiber connectors fabricated through Deep Proton Writing

Abstract

Deep Proton Writing (DPW) is a rapid prototyping technology allowing for the fabrication of micro-optical and micro-mechanical components in PMMA, which are compatible with low-cost replication technologies. Using DPW, a high-precision 2D fiber connector featuring conically-shaped micro-holes for easy fiber insertion, was realized. When populating these fiber connectors by fiber insertion and fixation, a critical issue is the accurate control of the fiber protrusion. The use of laser interferometry to measure the fiber's facet position with respect to the connector surface to within a few micrometers, is inconvenient in view of the measurement range as compared to the fiber dimensions. In this paper, we propose an interferometric method for in-situ monitoring of the fiber insertion depth, based on the phenomenon of low temporal coherence light interference in a Twyman - Green setup. In addition, achieving a few micrometers measurement range with low coherence light requires vertical scanning of the sample under test. The design of the experimental setup and the achieved measurement results are shown and discussed.