Polarisation-insensitive semiconductor optical amplifier gate switch with butt-jointed spot-size convertors - its uniformity

A spot-size converted polarisation-insensitive semiconductor optical amplif ier gate switch (SS-SOAG) for hybrid integration on a silica-based planer l ightwave circuit (PLC) platform has been fabricated and investigated. As a result, a SS-SOAG has been realised with low polarisation-dependent loss an d low coupling loss. This device operates over a wavelength range of more t han 50 nm, which suggests that it can be applied to various switching compo nents in wavelength routing switching systems. High speed gate operation ha s also been demonstrated. Fabrication tolerances of the mesa width and the laver thickness have been investigated at a submicron scale to ensure low p olarisation dependence and efficient coupling properties. Structural unifor mity in a wafer was accomplished using the proposed fabrication technique, which lads to characteristic uniformity of an eight-channel SS-SOAG array.