Daniel Daems

Optimizing deep lithography with protons for the fabrication of 2D fiber alignment structures

In this paper we present Deep Lithography with Protons (DLP) as a promising technology for the fabrication of mechanical fiber alignment structures accurately ordered in massive 2D arrays. The fabrication process consists of irradiating PMMA-resist layers with high-energetic proton beams through a lithographic mask with a well-defined circular shape, followed by a selective development of these irradiated zones. To increase the coupling efficiency, we can additionally integrate uniform spherical micro-lenses created by swelling the proton-bombarded zones in a monomer vapor. We highlight the influence of the etching time, the proton beam intensity and the absorbed doses in the PMMA layers on the diameters of the finally developed alignment holes. While selecting the correct process parameters, we prove DLP to be a suitable technology for the fabrication of circular micro-holes with diameters of 125&mum and 155&mum at the front and the back side of a 500&mum thick PMMA plate respectively. We finally illustrate the potentialities of these type of fiber holding plates to realize a user-friendly and accurate 2D fibre positioning component.

A cost-effective packaging for the environmental hardening of passive optical devices

A low cost packaging method, based on aluminium layered laminate sealing technology, is presented in this paper for the environmental hardening of planar waveguide splitters, filter WDM assemblies and other non-robust passive devices. Since the former two passive components will play a prominent role in PON networks and their upgrading scenarios, we questioned their long term reliability in uncontrolled outside plant environments by investigating their behavior in environmental testing as defined by Telcordia 1221. In particular, the optical performance of planar splitters and filter WDM assemblies from randomly chosen suppliers was monitored during temperature cycling and long term damp heat testing. A comparison was made between devices as packaged by the supplier and devices packaged in our Al laminate packaging. Although the packaging of planar waveguides has improved over the last years, our study convincingly demonstrates failure modes in the non-laminate packaged planar splitters. In addition, dramatic failures were also observed in filter WDMs assembled in modules for wide WDM, coarse WDM and dense WDM, which raise serious concerns about their long term environmental reliability. The laminate packaged devices however all pass the severe test conditions, exhibiting a better stability. This favors the use of our packaging method for the integration of planar splitters and filter WDM based assemblies in outside plant network elements.

Deep lithography with protons as an alternative fabrication technology for high-precision 2D fiber connector components

We present Deep Lithography with Protons (DLP) for the fabrication of ultra-dense fiber coupling elements which consist of circular, conical-shaped alignment features, ordered in a 2D array with high-precision pitches. This technology relies on the irradiation of PMMA-resist layers with a swift proton beam featuring a well-defined circular shape, followed by a selective development of these exposed zones. To increase the coupling efficiency, the DLP-technology allows to integrate uniform spherical micro-lenses, which are created by a controlled swelling of the proton-bombarded domains in a monomer vapor, in front of the micro-alignment holes. We will first discuss our work on the improvement of the DLP irradiation and development process step to enhance the coupling efficiency and the field-installability of the connector components. Furthermore, we will illustrate the optical design of micro-lens arrays and their integration in fiber connectors with improved tolerances.