Application of low-phonon energy glasses for optical amplification at 1.3 um

摘要

Abstract: We report on recent progress towards the application ofboth mixed cadmium halides and sulphide- based glassesas host materials for a Pr$+3$PLU$/-doped 1.3 micronoptical fiber amplifier. Both of these materials offerthe potential for higher gains than can be currentlyachieved in a Pr$+3$PLU$/- doped ZBLAN fiber.Fundamental glass properties, including optical andthermal characteristics, are compared. Losses of theseglasses in fiber form have been estimated andspectroscopic measurements are summarized. From thesestudies we show that quantum efficiencies over an orderof magnitude higher than those demonstrated withPr$+3$PLU$/-doped ZBLAN amplifiers are in principleobtainable. Measured efficiencies of 11% and 52% forthe Cd halide and Ga sulphide, respectively, areachieved, while 25% and 80% are predicted. Numericalmodelling allows comparison of the expected amplifierperformance. Thermal analysis has identified thechallenges which remain for the drawing of single modefibers and the results of preliminary fiber drawingtrials are described. The relative merits of each ofthe various glasses are considered and the challengesbefore a practical amplifier is achieved are outlined.!15