Silica PLC-Based Polarization Beam Splitter for 780 nm Free-Space Quantum Key Distribution Applications

Polarization beam splitter (PBS) for 780 nm wavelength was developed in order to be applied to free-space quantum key distribution applications. Short wavelength compared to telecommunication wavelength requires several differences in fabricating silica planar lightwave circuit devices. In this study, we fabricated silica PBS having polarization extinction ratio of 16.0 dB at 780 nm.

1. Introduction

Polarization beam splitter (PBS) using silica planar lightwave circuit (PLC) technology provides merits in miniaturization and integration with optical fiber or semiconductor optoelectronic devices. Thus they are widely used in high-capacity optical telecommunication module such as integrated dual-polarization coherent receiver [1].