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

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