Figure 2
From: Integrated multi-port circulators for unidirectional optical information transport
Fabrication process. (a) Cross-sectional view of the quantum well wafer used. (b) Schematic illustration of the intermixing process. SiO2, SiNx and Si-rich SiRNx capping layers are employed to spatially fine-tune the optical bandgap in the different sections required for this unidirectional system. (c) Photoluminescence response of the resulting three intermixed regions corresponding to ND (green), passive waveguide (blue) and SOA (red) segments. (d) Scanning electron microscope pictures at various stages of the fabrication process. The different components needed for the 4-port re-router (SOAs, NDs, mirrors, etc) are depicted.
