LOW-LOSS ACHIEVED IN SOL-GEL BASED SILICA-ON-SILICON INTEGRATED-OPTICS USING BOROPHOSPHOSILICATE GLASS

Polarisation-independent propagation losses of 0.2dB/cm are reported f or near-infrared silica-on-silicon channel guides formed using sol-gel borophosphosilicate glass deposited by repetitive spin coating and ra pid thermal annealing. The low loss is ascribed to a reduction in proc ess temperature, which has allowed a total glass thickness of 30 mu m. The use of two dopants allows the glass viscosity to be adjusted inde pendently of its refractive index, simplifying reflow and burial.