Characterization of optical coupling loss for AWG demultiplexer on SOI using butt-coupling method

We characterized the performance of the transmission spectrum in terms of insertion loss for 4 -channel silicon-on-insulator (SOI)-based arrayed waveguide grating (AWG) device ranging from 1471 nm to 1531 nm with 20 nm (~2500 GHz) channel spacing. The characterization was carried out using standard optical waveguide alignment system incorporated with butt-coupling method. Our main objective is to reduce coupling loss caused by the different mode-field diameter (MFD) between single mode fiber (SMF) and AWG device when butt-coupling method was used. Hence, fiber with conical tip of 2.0 μm spot diameter at 1/e² was introduced and the performance of coupling loss between standard 9/125 μm SMF and fiber with conical tip was compared where the latter reduced the optical coupling loss by 10%.