Integration of silicon microlenses to light sources for datacom and telecom applications

Passive alignment between the light source and coupling lenses may be one of the crucial and yet challenging technical fields to produce low-cost optical modules for telecom and datacom applications. In our presentation, we report the current status of our integration technologies of both surface and edge emitting type lasers with coupling lenses. We propose surfacemountable silicon microlens whose diameter is identical to a conventional optical fiber. The microlens can be passively aligned in the silicon v-groove to realize beam coupling between an edge emitting laser diode and an optical fiber. Coupling efficiency of -3.2dB between distributed feed-back laser diode and a single-mode fiber was experimentally confirmed. Precise rod shape is fabricated by D-RIE technology. We also report monolithic integration of the silicon substrate and a surface-emitting light source accomplished by direct bonding technology. The corresponding collimating lens is fabricated on the back-surface of the same silicon substrate. Passive alignment between the light source and the corresponding lenses are ensured by using a double-view mask aligner with sub-micron accuracy.