Design of an ultra-broadband and low-loss 3 dB power splitter from the 1.25 to 2.04 µm wave band.

As a key component of the beam splitting and combining in photonic integrated circuits, an optical power splitter requires the characteristics of compactness, broadband, and low loss. Here, we propose a 1×2 ultra-broadband 3 dB power splitter with a 5 µm long beam splitting area, based on the structure of a subwavelength grating. The 0.45 dB bandwidth of the TE mode achieves 790 nm from 1.25 to 2.04 µm. This power splitter has a large fabrication tolerance, exceeding more than 30 nm (±15 ) and obtains the desired power ratio. It is suitable for high-speed and large-capacity communication, wavelength division multiplexing systems, and other multi-wave interconnection applications.