Fabrication tolerant and wavelength independent arbitrary power splitters on a monolithic silicon photonics platform

Abstract

We experimentally demonstrate wavelength-independent couplers based on an asymmetric Mach-Zehnder interferometer on a monolithic silicon-photonics platform in a state-of-the-art CMOS foundry. The devices are also designed to exhibit fabrication tolerant performance for arbitrary splitting ratios. We have developed a semi-analytical model to optimize the device response and the reliability of the model is benchmarked against 3D-FDTD simulations. Experimental results are consistent with the simulation results obtained by the model and show uniform performance across different wafer sites with a standard deviation for the splitting ratio of only 0.6% at 1310 nm wavelength. The maximum spectral deviation of the splitting ratio (3-dB splitter) is measured to be 1.2% over a wavelength range of at least 80 nm and the insertion loss ranges from 0.08 to 0.38 dB. The wavelength-independent coupler has a compact footprint of 60 × 40 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>μ</mml:mi> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> .