2.0micron-band low-threshold single-frequency fiber laser of employing neodymium-holmium-ytterbium tridoped tellurate fiber

Abstract

The invention discloses a 2.0micron-band low-threshold single-frequency fiber laser of employing a neodymium-holmium-ytterbium tridoped tellurate fiber. The 2.0micron-band low-threshold single-frequency fiber laser comprises a single or double 808nm semiconductor laser pump source, a broadband fiber Bragg grating, a narrowband fiber Bragg grating, a gain fiber, a capillary encapsulation material,a wavelength division multiplexer, a photocoupler, an automatic temperature control system and a fiber combiner. According to the 2.0micron-band low-threshold single-frequency fiber laser, the energytransfer efficiency from neodymium ions to holmium ions is greatly improved by using high doping concentration of ions in a neodymium-holmium-ytterbium tridoped tellurate single-mode fiber and the energy transfer bridge function of ytterbium ions, thereby improving the luminous intensity of the holmium ions and solving the problems that an existing tellurate single-mode fiber laser is high in laser threshold, low in output power and complicated in structure; and meanwhile, the condition that only a single longitudinal mode exists in a laser cavity of a few centimeters is ensured by adopting a1-9cm short straight cavity structure through selecting a 3dB reflection spectrum width of the narrowband fiber Bragg grating, thereby achieving 2.0micron-band low-threshold single-frequency laser output.

Description

technical field [0001] The invention belongs to the field of optical fibers and optical fiber lasers, in particular to a 2.0 μm band low-threshold single-frequency optical fiber laser of a neodymium holmium ytterbium tridoped tellurate optical fiber. Background technique [0002] Fiber laser belongs to a new type of solid-state laser. The fiber acts as its gain medium. It has the advantages of good beam quality, high reliability, stability, excellent heat dissipation, and small size. It is known as the third-generation laser technology. typical representative. At present, fiber lasers have been widely used in manufacturing, aerospace, chemical industry, military and many other fields. Strategies Unlimited, an authoritative market research company in the United States, predicts that by 2017, the total annual revenue of global lasers is expected to exceed the $11 billion mark. CO in recent years 2 The annual income of lasers has not changed much, while the annual income of ...

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Problems solved by technology

However, the threshold power of the 2.0 μm band laser obtained by using these commonly used sensitizing ions is too high, reaching 260mW, and the slope efficiency is only 3%, and the maximum output power of the single-frequency laser is relatively small, only 5mW, and the slope efficiency is only 3% (see Li.K.et al.In-bandpumping of Tm doped single mode tellurite composite fibers.8982, 89821M-1-89821-6(2014). mode fiber laser, International Society for Optical Engineering Conference, 2014 Vol. 8982)), which is not conducive to the formation of low-threshold, high-power, compact and small-volume fiber lasers

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