Short-wavelength Tm-doped fiber laser with wave band of 1.6-1.7 microns

Abstract

The invention discloses a short-wavelength Tm-doped fiber laser with a wave band of 1.6-1.7 microns. The laser is characterized in that a pumping source emits pumping light in an Er-doped active fiber absorption band, and the Er-doped active fiber absorbs the pumping light; when the laser gain exceeds the loss of an Er-doped fiber laser resonant cavity formed by a first Er-doped fiber laser fiber grating and a second Er-doped fiber laser fiber grating which highly reflect a certain wavelength in the L-band, L-band laser near 1570nm is formed to oscillate in the resonant cavity; the Tm-doped active optical fiber absorbs 1570-nm laser and generates laser gain, short-wavelength laser with the wave band of 1.6-1.7 microns is formed under the action of a Tm-doped optical fiber laser resonant cavity formed by the Tm-doped optical fiber laser high-reflection optical fiber grating and the Tm-doped optical fiber laser output optical fiber grating, oscillates in the resonant cavity and is output through the Tm-doped optical fiber laser output optical fiber grating; and the Tm-doped active optical fiber is arranged in a resonant cavity of the Er-doped optical fiber laser.

Description

technical field [0001] The invention relates to the field of fiber lasers, in particular to a short-wavelength Tm-doped fiber laser in the 1.6-1.7 μm band. Background technique [0002] Tm (thulium)-doped fiber has a broad emission spectrum covering 1.6-2.1 μm, so fiber lasers using Tm-doped fiber as gain medium have extremely wide wavelength tuning potential. However, the current output wavelength of Tm-doped fiber lasers is mainly concentrated around the 1.9μm emission peak of Tm-doped fiber, and can be extended to 1.7-1.8μm and 2.0μm through certain wavelength selection measures. Reports are relatively rare. The reason is that on the one hand, the stimulated emission cross section of Tm ions at short wavelengths is significantly lower than that at 1.9 μm, which is similar to the situation at 2.0 μm at long wavelengths; The wavelength band is close to the absorption peak of Tm ions at 1.5-1.6 μm, and the stimulated absorption cross section is relatively large, which will ...

AI Technical Summary

Problems solved by technology

However, as mentioned above, limited by the reabsorption loss of Tm-doped fiber in the short wavelength band, it is generally not suitable to use longer Tm-doped fiber with higher doping concentration, and when the population inversion is realized in the two-level system lower laser level 3 h 6 A large part of the particles on the laser are pumped to the upper energy level of the laser 3 f 4 On the other hand, while reducing the reabsorption loss of the signal light, the absorption of the pump light is further reduced

Therefore, short-wavelength Tm-doped fiber lasers generally have the problem of poor absorption of pump light, high threshold and low efficiency. [1,2]

[0004] It can be seen from the above that the main contradiction that limits Tm-doped fiber to achieve efficient short-wavelength laser output in the 1.6-1.7 μm band lies in the contradiction between the obvious reabsorption loss of Tm-doped fiber for short-wavelength signal light and pump absorption.

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