Surface plasmon resonance-based silicon dual-core photonic crystal fiber polarization beam splitter at the mid-infrared spectral region

Abstract

In this paper, a novel silicon dual-core photonic crystal fiber (Si-DC-PCF) polarization beam splitter (PBS) based on the surface plasmon resonance effect is proposed. The mode-coupling characteristics between the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi></mml:math> - and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Y</mml:mi></mml:math> -polarized even and odd modes and surface plasmon polariton mode are analyzed by using the finite-element method and coupled-mode theory. The influences of the structure parameters of the Si-DC-PCF on the coupling length and coupling length ratio are investigated. The normalized output power of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi></mml:math> - and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Y</mml:mi></mml:math> -polarized modes in cores A and B and the corresponding extinction ratio are also discussed. By optimizing the structure parameters of the Si-DC-PCF, the PBS length of 192 µm and bandwidth of 830 and 730 nm in cores A and B are achieved. It is believed that the proposed Si-DC-PCF PBS can find important applications in mid-infrared laser and sensing systems.