Realistic opto-mechanical modelling of plastic optical fiber coupling systems

Today a lot of applications (datacommunication, automation, sensing, automotive . . . ) make use of plastic optical fibers (POF) to carry data over short distances. In this paper we will focus on the case study of a resonant cavity light emitting diode (RCLED) in combination with a POF. First we compare the optimal coupling efficiency of different coupling configurations (with ball lens, micro-lens and reflector) using non-sequential ray tracing software. Because we want to involve all specified external perturbations of the complete system we use Monte-Carlo based 3D opto-mechanical tolerancing to obtain the ideal optical system and its dimensions and tolerances. The definition of the best design will be based on a guaranteed minimum coupled power for a system subject to prescribed dimensional and geometrical deviations. To define the source model, we used extensive measurements. We import the measurement data of the light source to obtain realistic simulation results. Therefore we performed a full quantitative characterization of this source. More in particular we measured the total output power, the optical spectrum and the far-field pattern by using an integrating sphere, a spectrum analyzer and a goniometric radiometer respectively at different temperatures. We investigated two different situations, one where the RCLED emits light directly in air and the other where the light of this source first passes through epoxy before being measured in air like it is the case in a lot of coupling configurations.