Low-loss Polarization-Resolved Inline Optical Power Monitor Based on a Hybrid Ge/Si Structure

A low-loss polarization-resolved inline optical power monitor based on a hybrid Ge/Si structure has been proposed, which is compatible with standard CMOS fabrication process.The device incorporates polarization-resolved directional couplers to achieve low-loss, polarization-selective power extraction.Through rigorous design optimization, including shared grounding electrodes and tapered waveguide transitions, the device achieves insertion losses of 0.23 dB (TE) and 0.75 dB (TM) and responsivities of 11 mA/W (TE) and 10 mA/W (TM) across the C-band with a relatively compact footprint.Finite-difference time-domain (FDTD) simulations validate the device's performance, demonstrating its potential for on-chip polarization monitoring in integrated photonic systems.