Multi-band all-silicon TM-pass polarizer based on one-dimensional photonic crystals nanohole array

We propose an on-chip transverse magnetic (TM)-pass polarizer utilizing one-dimensional photonic crystals for multi-band operation. The TE₀ modes in the 1550/2000nm wave band are suppressed by carefully selecting the pitch lengths of the nanoholes, leveraging the bandgap of the nanohole array. Conversely, the TM₀ modes remain almost unaffected. The TM-pass polarizer employs a single-etched design on a standard 220 nm SOI platform and has a compact length of ∼ 17.9 µm. The simulated bandwidths (BWs) for polarization extinction ratios (PERs) > 20 dB and > 25 dB are about 210 nm and 195 nm for the 1550 nm wave band, and 265 nm and 240 nm for the 2000nm wave band. Moreover, the insertion losses (ILs) are ∼ 0.5/0.3 dB at wavelengths of 1550/2000nm, respectively. For the fabricated device, the measured BWs for PER > 20 dB and > 25 dB are evaluated to be larger than 100 nm for both 1550/2000nm wave bands. The measured ILs are 1/0.8 dB at wavelengths of 1550/2000nm. This straightforward and compatible design opens possibilities for the development of practical multi-band silicon photonic integrated circuits.