Archive | 2019
Thulium doped silica fiber laser operating in single-longitudinal-mode at a wavelength above 2 μm
Abstract
In this paper, a single frequency thulium doped silica fiber laser operating above 2 μm based on cascaded single-modemultimode- single-mode (SMS) fiber structures incorporating a Sagnac loop was experimentally demonstrated. Based on the theoretical analysis of the trans mission properties of the SMS fiber structure and mode selection characteristic of Sagnac loop, two cascaded SMS fiber devices with same multimode fiber lengths around 3.25 cm were used in our laser system to select the specific lasing wavelength above 2 μm as well as enhance the suppression of lasing around 1900 nm. And 6.5 m unpumped TDF was employed in Sagnac loop as saturable absorber to achieve single-frequency operation. Single-longitudinal-mode (SLM) operation of the fiber laser operating at 2004.05 nm was achieved with a signal to noise ratio (SNR) more than 60dB.