Ridge waveguide assisted highly efficient transverse-electric-pass polarizer based on a hybrid plasmonic waveguide.

An ultra-compact and low-loss transverse-electric (TE)-pass polarizer is proposed by utilizing a hybrid plasmonic ridge waveguide structure on a silicon-on-insulator platform. Since the transmission of a plasmonic polarizer is greatly influenced by the interaction between the metal and the optical field, there is a large insertion loss (IL) in the polarizer based on a hybrid plasmonic waveguide. Here, the electric field distribution and the periodic coupling between the fundamental transverse magnetic mode and plasmonic mode are taken into consideration to decrease the IL and shorten the length of the device. For a 4.2 μm-long polarizer, numerical simulations with the finite-differential-time-domain method show that it has a large extinction ratio (ER) of ∼29.5  dB with a low IL of 0.18 dB at the central wavelength 1550 nm. In addition, a more than 23 dB ER is achieved across a wide bandwidth of 100 nm.