Low-Loss Transponder Aggregator Using Spatial and Planar Optical Circuit

We propose a compact transponder aggregator (TPA) consisting of a wavelength selective switch (WSS) array and a direction switch array. It has no intrinsic splitting loss and therefore the number of ports can exceed that of a conventional multicast switch. A waveguide-based frontend that incorporates spatial beam transformers enables us to increase the number of ports and integrate multiple WSSs in a simple optical system. The direction switch array is integrated in the frontend. We describe an 8 × 24 prototype, which is the largest port count yet achieved for a TPA with no intrinsic splitting loss.