We present a design of a tapered optical waveguide mode-size converter from super luminescent diode(SLD)to silicabased planar lightwave circuits(PLCs).The mode-size converter is based on silica-based PLCs.By using three dimensional semivectorical beam propagation methods,tapered optical waveguides with different boundaries are simulated and compared with each other,where the factors of polarization-dependent loss and coupling loss are mainly focused on.The results show that the most influential factor for polarization-dependent loss is the ratio of the divergence angle of the vertical direction and the horizontal direction of SLD.The refractive index difference between core layer and cladding layer,core width of endface and taper length of the tapered waveguide influence coupling loss mostly,while the effect of all side boundaries is within 0.05dB.We also investigate the SLD misalignment tolerance and wavelength bandwidths impact on coupling loss.Futhermore,we examine the performance of the modesize converter based on a particular SLD which has a divergence angle of 45°×30°.By optimizing the parameters of the tapered waveguide,the coupling efficiency is increased to 62.4%and the polarization-dependent loss is reduced to 0.035dB.Meanwhile,it enables us to reduce the coupling loss variation to 0.05dB with a core width of endface fabrication tolerance of ±0.5μm and a taper length tolerance of ±0.5mm.The proposed mode-size converter has been demonstrated to be well performed,implying its application in the optical transceiver module using SLD as light source and hybrid integration of Ⅲ-Ⅴ semiconductor waveguiding devices and PLCs.