A polarization-independent, high-index contrast grating (HCG) with a single layer of cross stripes allowing simple fabrication is proposed. Since the cross stripes structure can be suspended in air by selectively wet-etching the layer below, all the layers can be grown at once when implemented for vertical-cavity surface-emitting lasers. We optimized the structure to have a broad and high reflectivity band centered at around 1xA0;x3BC;m using a finite difference time domain method, and obtained an 80xA0;nm high reflectivity band centered at 0.97xA0;x3BC;m in which the reflectivity exceeded 99.5 We also investigated the fabrication tolerances of the structure and found that, assuming careful optimizations of electron beam lithography for the precise grating width and dry-etching for the vertical sidewall, the suggested polarization-independent HCG can be fabricated using standard technologies.
Bibliographical noteThis paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-52-5-1049. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Ikeda, K., Takeuchi, K., Takayose, K., Chung, I-S., Mørk, J., & Kawaguchi, H. (2013). Polarization-independent high-index contrast grating and its fabrication tolerances. Applied Optics, 52(5), 1049-1053. https://doi.org/10.1364/AO.52.001049