A low transmission loss THz polarization splitter based on dual-core optical fiber

• A low loss THz polarization splitter based on dual-core optical fiber is designed.
• The dual-core fiber is with crossed dielectric strips in the fiber cross section.
• Most power of the field distributing in the air holes leads to low loss of the fiber.
• The polarization splitting is realized by coupling one and entrapping the other one.
• Any environmental contact will not disturb the field and induce additional losses.

We propose a design of a low loss terahertz polarization splitter based on a dual-core terahertz fiber with crossed dielectric strips in the fiber cross section. Low transmission loss is realized by extending the mode field to the air holes adjacent to the solid material. An 11.4-cm-long terahertz polarization splitter is obtained with the extinction ratio better than −15 dB and a bandwidth of 16 μm.