High-extinction-ratio silicon polarization beam splitter with tolerance to waveguide width and coupling length variations

Abstract

We demonstrate a compact silicon polarization beam splitter (PBS) based on grating-assisted contradirectional couplers (GACCs). Over 30-dB extinction ratios and less than 1-dB insertion losses are achieved for both polarizations. The proposed PBS exhibits tolerance in width variation, and the polarization extinction ratios remain higher than 20 dB for both polarizations when the width variation is adjusted from + 10 to -10 nm. Benefiting from the enhanced coupling by the GACCs, the polarization extinction ratio can be kept higher than 15 dB and the insertion loss is lower than 2 dB for both polarizations when the coupling length varies from 30.96 to 13.76 μm.

Ultra-compact and highly efficient silicon polarization splitter and rotator

“…4 The key elements for realizing the polarizationdiversity are polarization beam splitters (PBSs) 5,6 and rotators (PSRs). 7,8 Many types of siliconwaveguide PBSs and PSRs have been reported based on various structures, including directional coupler, 9,10 multimode interference (MMI), 11 hybrid plasmonic waveguide, 12 grating, 13 photonic crystal, 14 and so on.…”

Alignment-free characterization of polarizing beamsplitters

“…The reader may have noticed that all equations (3)(4)(5)(6)(7)(8) could also be written for a generic 3-port device, such as a regular beamsplitter. However, as discussed in Section IV-A, there is an uncertainty in the measurement introduced by the PDL of the circulator and the optical switch, which are unavoidable.…”

“…Traditionally, this measurement is performed using a highly coherent light source, such as a laser [4], [5], [6], [7], [8], [9], [10], [11]. The polarization state of a test light signal is matched with both axes -horizontal and vertical polarizations -of the device under test (DUT), using birefringent elements such as half-waveplates or fiber polarization controllers, depending on whether the DUT is a bulk or fiber-optical PBS, respectively.…”

Design of a Compact Polarization Splitter by Using Identical Coupled Silicon Nanowires

“…Dai [23] and Fukuda et al [24] have considered asymmetric directional coupler with a NW and slot waveguide, ignoring very long coupling length for TE mode compared to TM modes. Besides these, polarization splitters incorporating hybrid plasmonic waveguides [25], waveguide bend [26], arrayed waveguide grating (AWG) [27], liquid crystal [28], photonic crystal [29] and grating couplers [30] have also been reported.…”