Chalcogenide optical fiber couplers made by FBT method

Abstract We report on developing and characterization of chalcogenide FBT single mode fiber coupler for Mid-IR fiber optics applications. Single mode 6.3 μm core/123 μm cladding chalcogenide fibers of IHPS RAS with homemade polishing and standard PC/AFC connectors were utilized. Two fiber coupler geometries with angles α 1  = 70° and α 2  = 40° between the fibers were investigated and nature of excess loss has been studied. Excess loss and coupling ratios on time for both geometries were determined. Excess losses were measured to be 7 dB and 5 dB for α 1 and α 2 geometries respectively. For α 1 geometry 70:30 and for α 2 geometry 55:45 coupling ratios were achieved. For α 2 geometry coupling ratio at wavelength 2.64 μm was 63:37.