Broadband Arbitrary Ratio Power Splitters Based on Directional Couplers With Subwavelength Structure

We propose and demonstrate a 1×2 power splitter enabling arbitrary power splitting ratios. The device is based on a directional coupler with subwavelength structure in the coupling region and a trapezoid-structure in one arm. The measurement shows that arbitrary power splitting ratios, equal to 50:50, 60:40, 70:30, 80:20 and 90:10, can be obtained over an >80 nm bandwidth with an excess loss about 0.65 dB at 1550 nm, while the footprint is only 11.5 μm ×1.315 μm. The proposed arbitrary ratio power splitter shows promising application prospect in photonic integrated circuits.