Design and implementation of a Si 3 N 4 three-stigmatic-point arrayed waveguide grating with a resolving power over 17,000.

To provide a solution to the issue of the non-flat focal surface in traditional Rowland AWGs, we have designed and implemented a SiN three-stigmatic-point arrayed waveguide grating (TSP AWG) with three inputs, and a spectral resolving power over 17,000 has been achieved experimentally. The flat focal surface of this AWG can accommodate a butt-coupled detector array positioned at the output facet without any reduction of the resolving power of the edge channels. Therefore, it is particularly advantageous to some astronomical applications which require an AWG as a light-dispersing component to obtain a complete 2D spectrum. As a proof-of-concept for next generation devices, the multi-input aspect of the design accommodates multiple single-mode fibers coming into the AWG. In addition, because the device is implemented on a high-index-contrast platform (SiN/SiO), a compact size of ∼9.3 × 9.3 mm is achieved.