High-extinction-ratio directional-coupler-type polarization beam splitter with a bridged silicon wire waveguide

Abstract

We demonstrate an integrated polarization beam splitter (PBS) of a simple and compact device geometry with high polarization extinction ratios (PERs). A silicon PBS based on a three-waveguide directional coupler is numerically simulated for optimum device parameters, and fabricated experimentally. The measured PER values of the fabricated PBSs are 40.74 dB and 39.01 dB for transverse electric and transverse magnetic modes, respectively, and their corresponding insertion losses are 0.35 dB on average for a coupler length of about 29.4 μm.

High Performance Polarization Beam Splitter Based on Cascaded Directional Couplers Assisted by Effectively Anisotropic Structures

“…One can also use three or more cascaded DCs to improve the PBS performance by trading off the overall footprint. We believe that the performance of any PBS with a coupling mechanism of TEthrough and TM-cross, whose performance is mainly limited by TM polarization [8]- [12], [21], can be further improved by using our cascaded structure demonstrated in this paper. Moreover, higherperformance DCs can reduce the number of the cascaded DCs required and achieve more compact size.…”

“…Thus, the TE polarization can propagate through the same input waveguide throughout the DC while TM polarization will couple into another waveguide. The working bandwidth of this PBS strategy is usually limited by the TM polarization since it shows much more dispersion than the TE polarization case in the coupled waveguide system [8]- [12]. The improvement for the ER and bandwidth has been proposed by cascading two DCs for two-stage polarization filtering [6], [9]- [11].…”

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.…”

A broadband polarization splitter directional coupler based on tilted subwavelengh grating metamaterials

“…As this wavelength variation is, to first order, proportional to the square of the coupling length, a simple way to enhance the bandwidth of the device is to reduce its coupling length. To do so, here we insert a central silicon strip between the two arms of the directional coupler [10][11]. This central silicon strip increases the effective index of the even supermode, & !…”