Peter Dubruel

Ultrathin Optoelectronic Device Packaging in Flexible Carriers

This paper presents the development of an advanced packaging technique for commercially available optoelectronic devices. Vertical cavity surface emitting laser (VCSEL) diodes and photodiodes are thinned down to 20 μm thickness, and are embedded in flexible carriers, resulting in a 75-μm-thin package, which can be bent down to a bending radius of 2 mm. Electrical, optical, and mechanical characterization addresses the influence of thinning and embedding of bare optoelectronic chips on their main properties. Next to the embedded optoelectronics, also electrical ICs like amplifiers and drivers can be housed in the same thin flexible package, using an identical technology and layer build-up. Finally, this new packaging approach is demonstrated in two different integrated sensor applications and in an integrated optical interconnection. For the latter application, also waveguides and optical out-of-plane coupling elements are integrated in the package and the complete system reliability is assessed by accelerated aging tests.

An array waveguide sensor for artificial optical skins

We present a concept for an artificial optical skin, a flexible foil in which a novel type of optical force sensing elements is integrated. The principle relies on the change in coupling between two arrays of crossing polymer waveguides separated by a thin layer of soft silicone. When the exerted pressure is increasing, the distance between the waveguides decreases and consequently power is transmitted from one to another. A process flow to produce a proof of principle demonstrator with arrays of TruemodeTM waveguides embedded in silicone is described. In a second approach also the waveguides are fabricated in silicone using an embossing technique.