Silicon nitride offers low propagation losses and a wide transparency range, making it attractive for quantum photonics, but its low birefringence makes polarization control difficult. We demonstrate polarization beam splitters based on asymmetric directional couplers in silicon nitride at 950 nm and 1300 nm, with insertion losses below 1 dB and polarization extinction ratios of 20–30 dB.
Read the paper: Optics Letters 50, 2310–2313 (2025), doi: 10.1364/OL.560110