High Efficient Random Laser with Cavity Based on the Erbium-Doped Germanophosphosilicate Artificial Rayleigh Fiber

Abstract

The Erbium “random” laser, based on the artificial Rayleigh fiber, has been comparatively studied in detail under two different pump conditions: 974.5 and 1485 nm pumping wavelengths. The artificial Rayleigh 7-m-long fiber was used as a laser cavity, it was formed by the ultraviolet (UV) inscription of the uniform array of the weakly reflective fiber Bragg grating (FBG) during the fiber drawing process. The UV photosensitivity of the Erbium-doped fiber originated from the specially developed (germanophosphosilicate) core glass composition. The emission spectrum of the fabricated “random” fiber laser had a single narrow peak at the 1548 nm wavelength. It was clearly revealed that the extension of the laser cavity by the separate wavelength-matched 90%-reflective FBG resulted in a significant laser efficiency growth. The highest laser slope efficiency of 33% and the laser output power of 80 mW were reached in the FBG-modified cavity at the 974.5-nm-wavelength pumping. The continuous-wave operation mode of this laser has been confirmed. The laser linewidth value measured by the delayed self-heterodyne technique was about 550 Hz.

An Ytterbium-Doped Narrow-Bandwidth Randomly Distributed Feedback Laser Emitting at a Wavelength of 976 nm

“…The key to solving this problem may be the creation of a laser with randomly distributed feedback [25][26][27][28][29]. In such lasers, feedback is provided by Rayleigh reflection from an extended section of the fiber, or from an array of low-reflecting FBGs written along the length of the fiber.…”

Special Issue on Fiber Laser and Their Applications

“…Danila et al demonstrated a 976 nm Ytterbium-doped narrowbandwidth randomly distributed feedback laser [1]. Lasers that are operated at 1.5 µm wavelength have been obtained via different methods, such as random laser cavity [2], distributed Bragg reflector laser cavity [3], passive mode locking based on a saturable absorber [4], Brillouin random lasing oscillation, and four-wave mixing [5]. A 2 µm laser was demonstrated by Guanqu et al through the self-Q-switching technique [6].…”