Ultra-Compact Silicon-Based 1×8 Power Splitter Based on Digital Metamaterials

We present the design and experimental verification of an ultra-compact $1\times 8$ power splitter utilizing digital metamaterials. Our splitter leverages the direct binary search algorithm to optimize the pixelated design space, ensuring symmetric and efficient power distribution across the eight output waveguides. This design achieves a notably small footprint, low insertion loss, and excellent uniformity performance at the communication wavelength of 1550 nm. To validate our approach, we fabricated a $1\times 8$ power splitter on a silicon-on-insulator (SOI) platform, featuring ultra-compact length and space of just $5.33~\mu $ m and $56.12~\mu $ m2 respectively. This size represents a reduction of 1-2 orders of magnitude compared to previously reported values. Experimental results reveal an impressive insertion loss of 0.66 dB and a good uniformity of 0.42 dB at the center wavelength. Furthermore, the total loss remains below 1 dB across a wavelength range spanning from 1542.2 nm to 1553.5 nm. When compared to existing solutions, our designed splitter demonstrates superior performance in terms of size, insertion loss and uniformity. These attributes make this high-performance $1\times 8$ power splitter a promising candidate for applications in large-scale on-chip optical networks and optical phased arrays.