Optical fibers of As_2S_3 glasses: preparation and characterization

摘要

Chalcogenide glasses based on arsenic sulfide (As-2S-3), arsenic selenide or telluride are known to exhibit high optical nonlinearities which are necessary for advanced applications in telecommunications. Both, standard optical fibers and microstructured fibers have been fabricated from chalcogenide glasses. In this paper we deal with As-2S-3 solid core fibers and capillary fibers coated with a polymer jacket of UV acrylate. The guiding mechanism employing the reflection on boundary of high-index glass (a refractive index of about 2.4) and hollow cavity (n=l) was confirmed by ray-optic calculations. Fibers were drawn from input As-2S-3 rods and tubes. The rods were prepared from extra pure arsenic and sulfur by their melting in an evacuated ampoule. The tubes were prepared by using rotational melting technique in an evacuated ampoule rotating at 1600 rpm. Rods and tubes were elongated into fibers by using a fiber drawing facilities for preparation of optical fibers from soft optical glasses. Temperatures in a range 300-400 ℃ and drawing velocities of about 0.1 m/s were used. Fibers were prepared either without any polymeric jacket or they were provided by a jacket of UV acrylate (n ～ 1.5). Fibers with diameters from 0.2 to 0.4 mm were fabricated. Dimensions of prepared fibers were measured by optical microscopy without prior polishing. Transmission properties of prepared fibers were characterized by measuring angular distributions of output power at the wavelength of 670 nm. Optical losses of fibers exceeding 2 dB/m were determined by using the cut back method.