Abstract
A novel low-loss silicon photonic wire with 3-D taper couplers fabricated on silicon-on-insulator (SOI) by the deep etching and the thermal annealing processes was presented. The propagation loss and the coupler loss were measured to be 1.26dB/cm and 2.5dB/coupler [10][11]. In order to realize highly compact photonic integrated circuits based on silicon photonic wires, multimode interference (MMI) couplers were introduced for performing light splitting and combing due to the advantages of wide optical bandwidth, polarization independence and large fabrication tolerance. In this thesis, we have demonstrated monolithically integrated 2-D and 3-D MMI couplers with the novel silicon photonic wires via self-profile transformation [14]. The power splitting ratios of 50:50 and 15:85 were designed for preliminary study. For the 50:50 and 15:85 2-D MMI devices, the power splitting ratios were measured to be 46:54 and 10:90 for TE-polarized, and 48:52 and 13:87 for TM-polarized. The wide optical bandwidth according to the BPM simulation was also proven experimentally by measuring 2-D MMI devices. The preliminary measurement results for 3-D MMI couplers were also presented.