Beam Splitter · 1550 nm

This 50:50 beam splitter is designed on a silicon photonics (SOI) platform for operation at 1550 nm, with the optimization objective of minimizing insertion loss. The analytic estimates indicate a transmission efficiency of 97.2%, equivalent to an insertion loss of 0.123 dB (the same transmission expressed two ways), across a bandwidth of 90.0 nm. The directional coupler geometry uses a waveguide width of 0.5 µm, a gap of 0.23 µm, a coupling length of 18.055 µm, and a bend radius of 10 µm, yielding a compact footprint of 25.5 × 1.75 µm. The design achieves a fabrication score of 94.2/100, indicating good manufacturability while meeting the minimal-insertion-loss constraint. These figures are analytic estimates rather than the results of a full physical simulation.