Taper couplers for coupling between laser and silicon waveguide with large allowable tolerance

Abstract

A taper coupler with multimode input and single mode output is presented for coupling between edge emitting laser diode and silicon waveguide. The tapered coupler structure is optimized and tolerance for laser diode placement is studied. A typical coupling efficiency of -2dB is achieved from laser diode to silicon waveguide. With tolerance of +/-4µm laterally or vertically, the variation of the coupling efficiency is about 3dB. The tolerance is large compared with other methods. Tilting angle at laser diode and the small gap between tapered coupler and silicon waveguide also affect the overall coupling. From our studies, horizontal and vertical offsets are more critical for laser diode placement in order to have a good coupling. The new design can be applied to photonics packaging because it will make passive assembly easier by having larger tolerance for packaging compared with the conventional method with lens.

SIMPEL: Circuit model for photonic spike processing laser neurons

“…Although they have lower wall plug efficiencies, use more power and occupy larger spatial footprints than their VCSEL counterparts, their natural affinity for waveguide coupling and lithographically defined operating wavelengths post growth makes them a strong candidate for integrating photonic neural networks on a single chip. DFB lasers can be coupled into passive waveguides in III-V materials [52], can butt couple into waveguides on other materials such as silicon [53], or Active region equilibrium carrier density m −3 7.86×10 15 7.86×10 15 n eq,s SA region equilibrium carrier density m −3 7.86×10 15 7.86×10 15 can be defined within a silicon on insulator (SOI) substrate using techniques such as wafer bonding [54].…”