Search

Demands are increasing for ultrashort pulse laser in industrial applications, where the gain bandwidth of most optical fiber material is not wide enough, and developing a wide bandwidth gain medium is challenging. Glass–ceramic fibers containing Nd3+/Yb3+ co‐doped YCa4O(BO3)3 nanocrystals were fabricated by the molten core method and successive heat treatment. After a careful heat treatment, Nd3+/Yb3+ co‐doped YCa4O(BO3)3 nanocrystals were precipitated in the fiber core. Enhanced broadband near‐infrared (NIR) emission from 850 to 1150 nm (bandwidth: ∼252 nm) was obtained in the glass–ceramic fiber compared to that of precursor fiber. These results suggest that the Nd3+/Yb3+ glass–ceramic fibers are promising for broadband NIR optical amplifications and lasers. [ABSTRACT FROM AUTHOR]

Single‐crystal core multimaterial fibers have a wide range of applications in optics. Though some multimaterial fibers with single‐element crystal cores have been manufactured successfully, the preparation of binary and multielement crystals is limited by segregation or stoichiometry deviation during the thermal drawing and recrystallization process. This paper presents a new method, several times recrystallization by laser, to solve the crystal segregation problem of binary or multielement crystal core multimaterial fibers. [ABSTRACT FROM AUTHOR]

N-type bismuth telluride (Bi2Te3) based thermoelectric (TE) fibers were fabricated by thermal drawing and Bridgman annealing, and the influence of Bridgman annealing on the TE properties of n-type Bi2Te3-based TE fibers was studied. The Bridgman annealing enhanced the electrical conductivity and Seebeck coefficient because of increasing crystalline orientation and decreasing detrimental elemental enrichment. The TE performance of n-type Bi2Te3-based TE fibers was improved significantly by enhancing the power factor. Hence the power factor increased from 0.14 to 0.93 mW/mK2, and the figure-of-merit value is from 0.11 to 0.43 at ~300 K, respectively. [ABSTRACT FROM AUTHOR]

In the field of multimaterial optical fibers, the demand for high‐performance single‐crystal core glass‐clad multimaterial optical fibers is increasing. However, the applications of single‐crystal fibers are restricted by the complex fabrication processes and the slow growth of single‐crystal materials. Here, a two‐step method is demonstrated to achieve single‐crystal tellurium (Te) core fibers with high crystal quality over the length of the fiber. This method starts with the thermal drawing of a fiber preform into polycrystalline Te core multimaterial fibers (precursor fibers) that are long and mechanically stable. A 532‐nm continuous laser is then employed to recrystallize the Te core in the precursor fiber into a single crystal state along the entire length of the fiber. Experimental studies of these single‐crystal fibers demonstrate that the single‐crystal Te core fibers possess high transmittance (>90% at 2–10 μm) and high thermoelectric performance (ZT values from 0.03 to 0.13 at 300 K temperature). They are superior to previous reports and our previous work. This method works for fabricating various single‐crystal fibers and has important applications in the field of optical fibers, functional fibers, and their integrated devices. [ABSTRACT FROM AUTHOR]

A new type of thermally sensitive fibers with an antimony selenide (Sb 2 Se 3 ) core and phosphate glass cladding is demonstrated. The fibers were fabricated by a molten core method and maintained overall diameters ranging from 250 to 800 μm and core diameters of 35–200 μm. A 2.8 cm long Sb 2 Se 3 core fiber, electrically contacted to external circuitry through fiber end facets, exhibited a four orders of magnitude change in conductivity after the whole fiber was heated from 25 to 195 °C. In addition, the fiber exhibited enhanced photoconductivity under illumination. These results indicate that Sb 2 Se 3 core multimaterial fibers have promising applications in temperature sensing, optical switches and photodetectors. [ABSTRACT FROM AUTHOR]

Highly rare earth ions (RE-ions) doping phosphate glass fiber makes it possible to obtain high gain and high output power per unit length. However, high concentrations of RE-ions will cause concentration quenching and crystallization during the conventional rod-in-tube fiber drawing process. In this work, highly Er 3 + /Yb 3 + co-doped multi-component phosphate glasses were prepared by the melt-quenching method. Through thorough investigation of 1.53 μm luminescent properties of the glasses, optimal RE-ions were ascertained. The Er 3 + and Yb 3 + doping concentrations reach as high as 13.77 × 10 20 and 2.295 × 10 20 ions/cm 3 , respectively. Then the silicate-clad highly Er 3 + /Yb 3 + co-doped phosphate core multimaterial fibers were successfully fabricated by a molten core method. The multimaterial fibers have a large refractive index difference and good interface between the phosphate glass core and silicate glass cladding. An intense 1.53 μm emission was obtained from the multimaterial fiber. The results indicate that the highly Er 3 + /Yb 3 + co-doped multimaterial fibers are promising in applications that require high gain and high power from a short piece of active optical fiber. [ABSTRACT FROM AUTHOR]

• Glass-cladding GeSe core fibers were fabricated by a molten core drawing method. • The cores were found to be highly crystalline with extremely low oxygen. • The GeSe core fibers show sensitive photo response under illuminated states. • It possesses improved thermoelectric performance than that of bulk GeSe. Multimaterial fibers which integrate novel materials and/or structures into fiber configuration aim at developing multiple functionalities and high performance. Here, we demonstrate a kind of multimaterial fibers with crystalline GeSe core and K9 glass cladding by the molten core drawing method. The as-drawn fibers undergo a change in electrical conductivity when externally illuminated by an 808 nm HeNe laser. Furthermore, the Seebeck coefficient of the fibers is comparable with bulk GeSe, while the resistance is 3–4 magnitude lower than that. The results show that the GeSe core fibers have promising applications in optical switch and thermoelectric conversion field. [ABSTRACT FROM AUTHOR]