Hybrid photonic integration of active optoelectronic devices on polymer PLC platform
Hybrid integration of photonic components using planar lightwave circuit boards (PLC) as integration platform is considered to provide a powerful solution for implementing compact and small-footprint devices. Achievement of optimized performance is enabled by combining different materials technologies, and the modular approach guarantees a great deal of design flexibility and feasibility of rapid prototyping. Reduced fabrication costs are expected due to the principal applicability of waferscale and automated assembly processes. Polymer planar light wave circuits (P2LC) technology is attractive because it offers the potential of fairly simple and cost-effective fabrication using low-temperature batch processes, micro-machined processes, and cost-effective passive alignment. Polymer waveguides can be patterned into different geometries, allowing different optical signal processing functions such as wavelength routing, multiplexing and switching to be performed. The optoelectronic devices, such as laser diodes and photo diodes, and thin-film elements can be assembled on a polymer substrate (semi)-automatically by means of a pick-and-place technique. Therefore, polymer PLC boards can provide a convenient integration platform using hybrid technologies to combine passive optical waveguide devices and active chips to form different optical functional devices. In this paper, the authors present some key technologies in attaching single photodetectors (PD) and PD arrays to polymer waveguides by means of an integrated 45 deg turning mirror. The authors also demonstrate the butt-joint coupling between a distributed feedback laser and the P2LC board using HHI's proprietary curved stripe distributed feedback (CSDFB) devices. Various technological optimizations have been adopted for achieving low coupling loss (<3 dB) and thus high output power from the waveguide.