Power controllable gain switched fiber laser at\u2009~\u20093\xa0\u03bcm and\u2009~\u20092.1\xa0\u03bcm

Yiwen Shi,Jianfeng Li,Chen Zhu,Yong Liu,Chendong Lai,Hanlin Peng

doi:10.1038/s41598-020-80238-9

Abstract

Based on a hybrid pumping method consisting of a 1150 nm continuous-wave pump source and a 1950 nm pulsed pump source, we demonstrate a power controllable gain-switched fiber laser in dual wavebands at ~ 3 μm and ~ 2.1 μm. Different pumping schemes for pumping a Ho3+-doped ZBLAN fiber are studied. Using only the 1950 nm pulsed pump source, ~ 2.1 μm gain-switched pulses with single and double pulses are obtained separately at different pump powers. This phenomenon indicates that the 1950 nm pulsed pump source acts as a modulator to trigger different states of the ~ 2.1 μm pulses. Moreover, by fixing the 1150 nm pump power at 3.259 W and adjusting the 1950 nm pump power, the output power of the ~ 2.1 μm gain-switched pulsed laser is flexibly controlled while the ~ 3 μm laser power is almost unchanged, inducing the maximum output powers of 167.96 mW and 260.27 mW at 2910.16 nm and 2061.65 nm, respectively. These results suggest that the comparatively low power of the ~ 2.1 μm gain-switched pulsed laser in dual-waveband laser can be efficiently overcome by reasonably controlling the 1950 nm pump power.

Highlights

Based on a hybrid pumping method consisting of a 1150 nm continuous-wave pump source and a 1950 nm pulsed pump source, we demonstrate a power controllable gain-switched fiber laser in dual wavebands at ~ 3 μm and ~ 2.1 μm
We firstly studied the performances of the output laser in different pumping schemes, i.e., while pumping with only the 1150 nm CW pump source, only the 1950 nm pulsed pump source, and variable 1150 nm CW pump source with the maximum 1950 nm pulsed pump power
When pumping with the variable 1150 nm CW pump source at the maximum 1950 nm pulsed pump power, the pulse states at ~ 2.1 μm changed from multiple pulses to single pulse until the ~ 2.1 μm pulse disappeared, which is similar to the phenomena reported in our previous publication[24]

Summary

Introduction

Based on a hybrid pumping method consisting of a 1150 nm continuous-wave pump source and a 1950 nm pulsed pump source, we demonstrate a power controllable gain-switched fiber laser in dual wavebands at ~ 3 μm and ~ 2.1 μm. Demonstrations of dual-waveband mid-infrared pulsed lasers using holmium fluoride fiber have been studied[7,21,22,23,24], owing to the transitions of the 5I6 → 5I7 and 5I7 → 5I8 which realize the emissions of ~ 3 μm and ~ 2.1 μm simultaneously Among these studies, methods such as active/passive Q-switching and gain-switching have been adopted[25,26,27]. The output characteristics of the Ho3+-doped ZBLAN fiber laser in different pumping schemes are studied in detail

Methods

Results

Conclusion