Low-loss hybrid plasmonic TM-pass polarizer using polarization-dependent mode conversion

Abstract

A low-loss hybrid plasmonic transverse magnetic (TM)-pass polarizer has been demonstrated utilizing polarization-dependent mode conversion. Taking advantage of the silicon hybrid plasmonic slot waveguide (HPSW), the unwanted transverse electric (TE) fundamental mode can be efficiently converted first to a TM higher-order mode and then suppressed by a power combiner, while the retained TM fundamental mode can pass through with negligible influence. Since the HPSW feature both strong structural asymmetry and a small interaction area in the cross-section between the metal and optical field, the optimized insertion loss of the device is as low as 0.4 dB. At the wavelength of 1550 nm, the extinction ratio is 28.3 dB with a moderate footprint of 2.38 μm × 10 μm . For the entire C band, the average reflection of the TE mode is suppressed below − 14 dB , and the extinction ratio is over 18.6 dB. This work provides another more efficient and effective approach for better on-chip polarizers.