Ultra-high extinction ratio polarization beam splitter with extreme skin-depth waveguide

Journal Article · Wed Apr 28 00:00:00 EDT 2021 · Optics Letters

DOI:https://doi.org/10.1364/OL.420824· OSTI ID:1779911

Ahmed, Syed Z.; Ahmed, Ishtiaque; Mia, Md Borhan ; Jaidye, Nafiz; Kim, Sangsik

In this Letter, we present a high extinction ratio and compact on-chip polarization beam splitter (PBS), based on an extreme skin-depth (eskid) waveguide. Subwavelength-scale gratings form an effectively anisotropic metamaterial cladding and introduce a large birefringence. The anisotropic dielectric perturbation of the metamaterial cladding suppresses the TE polarization extinction via exceptional coupling, while the large birefringence efficiently cross-couples the TM mode, thus reducing the coupling length. We demonstrated the eskid-PBS on a silicon-on-insulator platform and achieved an ultra-high extinction ratio PBS ( $\approx \; <\#comment/>60\mathrm{d}\mathrm{B}$ for TE and $\approx \; <\#comment/>48\mathrm{d}\mathrm{B}$ for TM) with a compact coupling length ( $\approx \; <\#comment/>14.5\text{µ <\#comment/>}\mathrm{m}$ ). The insertion loss is also negligible ( $<\; <\#comment/>0.6\mathrm{d}\mathrm{B}$ ). The bandwidth is $>\; <\#comment/>80$ (30) nm for the TE (TM) extinction ratio $>\; <\#comment/>20\mathrm{d}\mathrm{B}$ . Our ultra-high extinction ratio PBS is crucial in implementing efficient polarization diversity circuits, especially where a high degree of polarization distinguishability is necessary, such as photonic quantum information processing.

• Sponsoring Organization: USDOE
• Grant/Contract Number: 89233218CNA000001; NA-0003525
• OSTI ID: 1779911
• Journal Information: Optics Letters, Journal Name: Optics Letters Vol. 46 Journal Issue: 9; ISSN 0146-9592
• Publisher: Optical Society of America
• Country of Publication: United States
• Language: English