The authors report a highly polarisation-independent InP arrayed waveg
uide filter using square cross-section waveguides. A TE-TM shift of <
0.01nm and polarisation-dependent loss of < 0.1dB was obtained for an
8 x 1.6nm filter operating at 1.5 mu m. Fibre-to-fibre insertion loss
was just 6.7 - 7.3dB, with channel crosstalk < - 26dB.