All-chalcogenide single-mode optical fiber couplers

We demonstrate the fabrication of all chalcogenide single-mode optical fiber couplers including broadband couplers, wavelength division multiplexers, and polarization beamsplitters. The functionality of each coupler is engineered with a careful design of geometry. As a result, broadband couplers can be set to any arbitrary coupling ratio. Wavelength division multiplexers provide a coupling extinction ratio up to 35 dB, and polarization beamsplitters provide a polarization extinction ratio up to 18 dB.