Integrated photonic high extinction short and long pass filters based on lateral leakage

In this contribution we present a new approach to achieve high extinction short and long pass wavelength filters in the integrated photonic platform of lithium niobate on insulator. The filtering of unwanted wavelengths is achieved by employing lateral leakage and is related to the bound state in the continuum phenomenon. We show that it is possible to control the filter edge wavelength by adjusting the waveguide dimensions and that an extinction of hundreds of dB/cm is readily achievable. This enabled us to design a pump wavelength suppression of more than 100 dB in a 3.5 mm long waveguide, which is essential for on-chip integration of quantum-correlated photon pair sources. These findings pave the way to integrate multi wavelength experiments on chip for the next generation of photonic integrated circuits. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study presents a new approach to achieve high extinction short and long pass wavelength filters in the integrated photonic platform of lithium niobate on insulator. By adjusting the waveguide dimensions, it is possible to control the filter edge wavelength and achieve high extinction dB/cm. These findings pave the way for integrating multi wavelength experiments on chip for the next generation of photonic integrated circuits.