Ultracompact and ultrabroadband arbitrary ratio power splitter using subwavelength gratings

Abstract

An ultracompact and ultrabroadband arbitrary ratio power splitter based on adiabatically tapered silicon waveguides, with subwavelength gratings in the coupling region, is proposed and demonstrated experimentally. Various power splitting ratios (PSRs) can be implemented by flexibly manipulating the gap of two adjacent tapered waveguides. The wavelength dependence is greatly reduced by introducing subwavelength gratings. Simulation results show that our proposed device has a 400 nm (1300 nm–1700 nm) bandwidth with an insertion loss <0.5dB for PSRs of 50:50, 60:40, 70:30, 80:20, and 90:10, and the corresponding total device length is only 2.9 µm. The experimental results indicate that the insertion loss is lower than 0.82 dB over a wide bandwidth of 80 nm, and there is a PSR variation less than 2.5% in the range of 1530 nm to 1610 nm.