High-Performance Polarization-Independent Beam Splitters and MZI in Silicon Carbide Integrated Platforms for Single-Photon Manipulation
Xiaodong Shi, Yaoqin Lu, Nianhua Peng, Karsten Rottwitt, Haiyan Ou
Abstract
Siliconcarbide (SiC), having various intrinsic color centers, is a highly promising optical material for making monolithic quantum integrated photonic circuits, by combining the single-photon sources with the integrated photonic components in SiC integrated platforms. Based on this quantum-material platform, we propose polarization-independent 1 × 2 and 2 × 2 multimode interference based beam splitters and Mach-Zehnder interferometers (MZI) for single-photon manipulation with unknown polarization states. We experimentally demonstrate that these devices exhibit excellent performances with incident light at both high power ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$>$</tex-math></inline-formula> −10 dBm) and ultra-low power ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$< $</tex-math></inline-formula> −100 dBm). The 1 × 2 and 2 × 2 beam splitters have low average loss of 1 dB and 1.5 dB, with a wide bandwidth of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$>$</tex-math></inline-formula> 100 nm and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$>$</tex-math></inline-formula> 70 nm, respectively. The MZI exhibits high transmittance, with a visibility of 98.3% and 97.6% for the high-power measurement and an even higher visibility of 99.0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 0.4% and 98.7 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 0.6% for the ultra-low power measurement, for the TE and TM polarizations, respectively.