Broadband and Wavelength-Dependent Chalcogenide Optical Fiber Couplers

We present optical fiber couplers made of As₂Se₃ glass. Broadband and wavelength-dependent couplers are fabricated from fibers of engineered core/cladding diameter ratios. Coupling ratios at the through-cross ports ranging from 50%–50% down to 1%–99% are achieved. The transparency of As₂Se₃ glass over the spectral range of 1.5–12.0 <inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> makes it a material of prime interest for the fabrication of mid-infrared couplers.