%0 Journal Article
%T Tunable Single-Longitudinal-Mode High-Power Fiber Laser
%A Jonas K. Valiunas
%A Gautam Das
%J International Journal of Optics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/475056
%X We report a novel CW tunable high-power single-longitudinal-mode fiber laser with a linewidth of 9£¿MHz. A tunable fiber Bragg grating provided wavelength selection over a 10£¿nm range. An all-fiber Fabry-Perot filter was used to increase the longitudinal mode spacing of the laser cavity. An unpumped polarization-maintaining erbium-doped fiber was used inside the cavity to eliminate mode hopping and increase stability. A maximum output power of 300£¿mW was produced while maintaining single-longitudinal-mode operation. 1. Introduction Fiber lasers are established as robust and reliable devices with a variety of applications in industry and medicine due to their unique characteristics, such as all-fiber designs, compact size, cost-effective production and operation, and the no need for realignment or external cooling. High-power single-wavelength and multiwavelength infrared fiber lasers are very attractive for applications in optical communications, sensing, spectroscopy, biomedical instrumentation, and nonlinear optics. The continued progress in fiber pumping techniques, advanced fiber designs, and fabrication processes, as well as the availability of high-power pump diodes, has assisted in the development of high-power fiber lasers [1¨C5]. Fiber lasers have found applications in temperature and strain sensors [6¨C11], medical diagnostics [12¨C14], and industrial processing [15]. High-power fiber lasers using erbium-ytterbium codoped fibers as the gain medium, which operates in the eye-safe (1.5£¿¦Ìm to 1.6£¿¦Ìm) spectral range, can now compete with traditional solid-state bulk lasers. The applications of recently reported single-wavelength [16, 17] and multiwavelength [18, 19] high-power fiber lasers were limited due to large linewidth of the lasing wavelength, multi-longitudinal-mode oscillations, small tuning range, and complex designs. In this paper we present a novel tunable, high-power, single-wavelength, single-longitudinal-mode, fiber ring laser. 2. Experimental Setup The experimental setup of the fiber laser is shown in Figure 1. The resonant cavity consists of a high-power polarization-independent optical isolator (OI), which guaranteed the unidirectional propagation and thus eliminated the spatial hole-burning effects [20]; an all-fiber polarization controller; a commercially available tunable fiber Bragg grating (TFBG) with a tuning range of 10£¿nm (1565£¿nm¨C1575£¿nm); a 4£¿m long double-clad erbium-ytterbium codoped (DC-EYDF) fiber with core/cladding diameters of 10/131£¿¦Ìm which was used as the gain medium. In general to produce high output power from a
%U http://www.hindawi.com/journals/ijo/2012/475056/