Packaging of waveguide devices based on bulk silicon MEMS technology

The coupling between fibers and waveguides is the key technique in packaging waveguide devices. The misalignment between fibers and waveguides will induce the insert loss. When the insert loss is less than 3 dB, the alignment tolerance of fibers and waveguides will be less than ± 0.5 μm. It's quite difficult for conventional ways, especially packaging array waveguide and multifibers. MEMS techniques can fabricate the micro-pattern smaller than 1 μm. We can fabricate the aligning groove for the fibers and waveguides in the silicon by MEMS techniques. These grooves guarantee the alignment precision. The key techniques are aligning the crystal direction and silicon anisotropic etching. Basing on analyzing kinds of losses in butt-coupling between fibers and waveguides, the aligning grooves etched in silicon substrate is used as packaging bench. And we compare the difference between the U-groove etched in (110) silicon and V-groove formed in (100) silicon as the aligning groove, Then bring forward a self-aligning method for 1 × 8 power splitter and fibers.