Compact and efficient polarization splitter based on dual core microstructured fiber for THz photonics

Abstract

We consider a dual core polyethyelene microstructured fiber with teflon and air inclusions in the core region for achieving compact and efficient polarization splitting at THz frequencies. The teflon inclusions form slit-like structure that helps in shifting the degeneracy point to lower frequencies. The y-polarized light couples from one core to the other within a very small device length of a few cm. Modal fields, effective indices, device length, extinction ratio and different losses have been calculated, which provide a handle to reduce the polarization splitting length at frequencies below and above ~ 0.7THz. Extinction ratios are found to be significantly high in a broad frequency range, e.g. a value of ~ 70 dB for x-polarization and ~ 45 dB for the y-polarization with about 2.1 cm device length at 1 THz. This device length is more than 30 times shorter than previously reported values. However, it attains a maximum device length of 21.6 cm at ~ 0.7 THz, which is also shorter than the corresponding earlier reported value.