Nanoscience and Nanotechnology Commons^™

A Taper To Reduce The Straight-To-Bend Transition Loss In Compact Silicon Waveguides, Hao Shen, Li Fan, Jian Wang, Justin Wirth, Minghao Qi

Jian Wang

Strong confinement of light in silicon waveguides allows for sharp bends and, as a result, high-density integration. However, the mode transition loss between the straight and bent portions of a silicon waveguide begins to affect the device performance when the bending radius becomes small. In this letter, we show that a transition region with a step taper between the straight and bent portions of the waveguide can effectively reduce this transition loss. This is demonstrated by measuring the intrinsic round-trip losses of micro-racetrack resonators, where ultralow loss can be precisely characterized according to the quality (Q)-factor change. The results show …