2 × 2 InGaAlAs/InAlAs multiquantum well (MQW)directionalcoupler waveguide switch modules integrated with spotsize convertors

Abstract
The authors report the first ever fully packaged practical 2 × 2 InGaAlAs/InAlAs MQW waveguide switch modules integrated with newly proposed efficient spotsize convertors. The connector-to-connector insertion loss and crosstalk of switch modules are 16 and −15 dB, respectively. The spotsize conversion loss, including coupling loss to arrayed polarisation-maintaining (PANDA) singlemode fibres (SMFs) is, on average, 2.3 dB per port.