On-chip polarization splitter based on a multimode plasmonic waveguide

Abstract

The miniaturization of polarization beam splitters (PBSs) is vital for ultradense chip-scale photonic integrated circuits. However, the small PBSs based on complex hybrid plasmonic structures exhibit large fabrication difficulties or high insertion losses. Here, by designing a bending multimode plasmonic waveguide, an ultrabroadband on-chip plasmonic PBS with low insertion losses is numerically and experimentally realized. The multimode plasmonic waveguide, consisting of a metal strip with a V-shaped groove on the metal surface, supports the symmetric and antisymmetric surface plasmon polariton (SPP) waveguide modes in nature. Due to the different field confinements of the two SPP waveguide modes, which result in different bending losses, the two incident SPP waveguide modes of orthogonal polarization states are efficiently split in the bending multimode plasmonic waveguide. The numerical simulations show that the operation bandwidth of the proposed PBS is as large as 430 nm because there is no resonance or interference effect in the splitting process. Compared with the complex hybrid plasmonic structure, the simple bending multimode plasmonic waveguide is much easier to fabricate. In the experiment, a broadband (Δλ ≈ 120 nm) and low-insertion-loss (<3 dB with a minimum insertion loss of 0.7 dB) PBS is demonstrated by using the strongly confined waveguide modes as the incident sources in the bending multimode plasmonic waveguide.

Multi-Directional Plasmonic Splitter and Polarization Analyzer Based on the Catenary Metasurface

“…However, we note here that the polarization-controlled SPPs excitation examined thus far depend either on x-polarized and y-polarized incidences or on LCP and RCP incidences, only two polarization states of incident light can be splitted in one structure [20][21][22]. In order to address this problem, Shen et al demonstrated a bi/tridirectional SPPs splitter based on a slanted gold mushroom array [23], achieving different responses to multiple incident light polarization states.…”

Nanophotonic Polarization Routers Based on an Intelligent Algorithm

“…[ 3,4 ] As an essential component of on‐chip integrated photonic devices, polarization router can separate and steer light with different polarizations of transverse electric (TE) and transverse magnetic (TM) modes into different output ports, so as to realize polarization division multiplex of channels. In the past few years, polarization routers are generally realized based on gratings, [ 5–8 ] optical waveguides, [ 9–12 ] photonic crystals, [ 13–16 ] plasmonic structures, [ 17–20 ] metamaterials [ 21–23 ] or some other structures. [ 24–27 ] Polarization routers based on gratings or waveguides usually possess simple configurations and high extinction ratio, but the large size restricts the practical applications for on‐chip dense integration.…”

“…[ 13,16 ] The plasmonic polarization routers are broadband and have smaller size, but usually possess large loss. [ 17,18 ] Polarization routers based on metamaterials have high efficiency, but the fabrication process is complicated and the size is relatively large. [ 21,23 ] Large size and low‐efficiency excitation of traditional design cause the polarization routers to be difficult to meet the requirements of high‐density on‐chip integration.…”