• Anders, Krzysztof Paweł
• Piramidowicz, Ryszard
• Osuch, Tomasz
• Komorowski, Paweł
• Zdulska, Urszula
• Markowski, Konrad

Abstract

Multicomponent ZBLAN glass (53%ZrF4-20%BaF2-4%LaF3-3%AlF3-20%NaF) has been widely investigated as potential host for rare-earth doped fiber lasers and amplifiers due to its low intrinsic loss, broad transmission window and small phonon energy. Despite these impressive advantages, ZBLAN offers much lower mechanical stability and hardness than a silica glass, typically used as an active medium in fiber lasers and amplifiers operating in near infra-red spectral range. Hybrid construction, consisting of active fluoride and passive silica fibers may enable simultaneous benefiting both from excellent luminescent properties of RE3+ doped ZBLAN glass and all advantages of low-cost, reliable and easily manufactured fiber-optic components made of silica glass and deployed as a remaining elements of resonator in the most attractive, all-fiber geometry. The key problem to solve on the way of developing such hybrid laser is low-loss and stable interface between silica and fluoride fiber.In this work we present all-fiber hybrid laser operating at 1.55 μm, based on Er3+:ZBLAN active medium and silica fiber-optic components of optical resonator (including Fiber Bragg Gratings - FBGs), which has been developed to verify applicability and usefulness of this type of construction. For this purpose we developed a glue splicing technique (also called a “cold splicing”) to effectively connect silica and fluoride fiber in a stable and reliable way. UV-curable acrylate optically transmitting adhesive has been applied to provide mechanical and thermal stability of splice. The adhesive has refractive index similar to ZBLAN fiber, small shrinkage during cure time and good thermal properties, which is critical to obtain low-loss splice.The optical properties and key parameters of active fiber and FBGs were determined by standard spectroscopic measurements and calculations. These were in turn used to develop the model of laser and predict laser action properties. Finally, all-fiber laser based on combination of erbium-doped ZBLAN and passive silica fibers was set up and carefully examined under 1490 nm and 980 nm pumping. Main performance parameters of laser action have been measured and compared with numerical computation.The obtained results confirmed the applicability and usefulness of hybrid fiber laser design, giving an excellent starting point for further development of this kind of lasers.

Topics

• impedance spectroscopy
• glass
• glass
• hardness
• Erbium