Ultra-broadband, compact, and high-reflectivity circular Bragg grating mirror based on 220 nm silicon-on-insulator platform

Abstract

A compact (4.49 μm x 4.54 μm) and ultra-broadband circular Bragg grating mirror with relaxed fabrication requirements is proposed and demonstrated based on the 220 nm silicon-on-insulator (SOI) platform. Based on FDTD-simulations, the proposed grating mirror can achieve a reflectivity of >90% over a ultrabroad bandwidth of 500 nm (1263 - 1763 nm), and a high reflectivity of >95% over a broad bandwidth of 397 nm (1340 - 1737 nm), which covers the entire E- to U-bands. The circular grating is fabricated, and the experimental measurement results exhibit a high reflectivity of 93% - 98% within the measured band of 1530 to 1610 nm, which agrees well with simulations. Based on the proposed broadba..