Replication of self-centering optical fiber alignment structures using hot embossing

With the demand for broadband connectivity on the rise due to various services like video-on-demand and cloud computing becoming more popular, the need for better connectivity infrastructure is high. The only future proof option to supply this infrastructure is to deploy "fiber to the home" (FTTH) networks. One of the main difficulties with the deployment of FTTH is the vast amount of single-mode fiber (SMF) connections that need to be made. Hence there is a strong need for components which enable high performance, robust and easy-to use SMF connectors. Since large-scale deployment is the goal, these components should be mass-producible at low cost. We discuss a rapid prototyping process on the basis of hot embossing replication of a self-centering alignment system (SCAS) based on three micro-springs, which can position a SMF independently of its diameter. This is beneficial since there is a fabrication tolerance of up to 1 mu m on a standard G.652 SMF's diameter that can lead to losses if the outer diameter is used as a reference for alignment. The SCAS is first prototyped with deep proton writing (DPW) in polymethylmethacrylate (PMMA) after which it is glued to a copper substrate with an adhesive. Using an electroforming process, a nickel block is grown over the PMMA prototype followed by mechanical finishing to fabricate a structured nickel mould insert. Even though the mould insert shows non-ideal and rounded features it is used to create PMMA replicas of the SCAS by means of hot embossing. The SCAS possesses a central opening in which a bare SMF can be clamped, which is designed with a diameter of 121 pm. PMMA replicas are dimensionally characterized using a multisensor coordinate measurement machine and show a central opening diameter of 128.3 +/- 2.8 mu m. This should be compared to the central opening diameter of the DPW prototype used for mould formation which was measured to be 120.5 mu m. This shows that the electroforming and subsequent replication process is possible for complex micro-scale components and could be accurate after optimisation. We characterized the sidewall roughness of PMMA replicas using a non-contact optical profiler, resulting in a root-mean-square roughness of 48 nm over an area of 63.7 mu m x 47.8 mu m. This low sidewall roughness is especially important in the replication of high aspect ratio structures to facilitate demoulding since the sidewalls cause the most friction with the mould insert.

Jaar van publicatie:2016

Trefwoorden:DEEP, COMPONENTS

Auteurs:International

Toegankelijkheid:Open