Four-channel polarisation-insensitive SOA gate array integrated with butt-jointed spot-size converters

Spot-size converted four-channel polarisation-insensitive semiconductor optical amplifier (SOA) gate arrays have been fabricated for multi-channel wavelength division multiplexing applications. The performance of this device has good uniformity. This device affords a drastic improvement in coupling properties with a low polarisation dependence (< 0.2 dB).