Experimental characterization of hydrogenated amorphous silicon photonic crystal waveguides

Summary form only given. Photonic crystal (PhC) slab waveguides are very compact structures that are able to tightly confine light. This property makes them fundamental in the conception of highly integrated photonic devices. In our work we report the first experimental results, to our knowledge, of PhC waveguides fabricated using the hydrogenated amorphous silicon (a-Si:H) platform. From recent investigations, a-Si:H has emerged as a possible new material platform for nonlinear photonics [1-4]. The associated fabrication process can be fully CMOS compatible. Furthermore, a-Si:H can exhibit both high nonlinear Kerr index (n₂) and low two-photon absorption (β_TPA) at telecom wavelengths. Its nonlinear figure of merit (FOM=n₂/ (β_TPA*λ)) can be as high as 5 [4], which is critical for creating efficient nonlinear photonic devices. In comparison, crystalline silicon (c-Si) exhibit a high Kerr coefficient but its poor FOM (~0.3-0.5) prevents it from being used in some applications.