Wide wavelength selectable all-fiber thulium doped fiber laser between 1925 nm and 2200 nm

Jianfeng Li,Lin Zhang,Hongyu Luo,Zhongyuan Sun,Yong Liu,Kaiming Zhou,Zhijun Yan

doi:10.1364/oe.22.005387

Abstract

We demonstrate an all-fiber Tm(3+)-doped silica fiber laser operating at a wide selectable wavelength range by using different fiber Bragg gratings (FBGs) as wavelength selection elements. With a specifically designed high reflective (HR) FBG and the fiber end as an output coupler, the lasing in the range from 1975 nm to 2150 nm with slope efficiency of >30% can be achieved. By employing a low reflective (LR) FBG as the output coupler, the obtainable wavelengths were extended to the range between 1925 nm and 2200 nm which is the reported longest wavelength from the Tm(3+)-doped silica fiber lasers. Furthermore, by employing a FBG array in the laser cavity and inducing bend loss between adjacent FBGs in the array, six switchable lasing wavelengths were achieved.

Highlights

Laser sources locating at eye-safe 2 μm region, especially for operation wavelengths in the atmospheric transmission window between 2.05 μm and 2.3 μm, have many significant applications in atmospheric lidar measurement [1], remote sensing [2], medical surgery [3,4,5], etc
Sacks et al employed a diffraction grating to demonstrate a tunable Tm3+-doped double clad silica fiber laser, pumped by two 790 nm diodes, with the reported longest edge at ~2188 nm from Tm3+-doped silica fiber laser, the slope efficiency at 2188 nm was less than 6% [19]
It is observed that the laser emitting at 2198.4 nm can still operate at a comparatively high slope efficiency of 17.82% with a low threshold of 4.78 W and a maximum output power of 0.55 W, which can be ascribed to the high feedback provided by the pair of fiber Bragg gratings (FBGs) and strengthened re-absorption induced by long active fiber and large ions concentrations

Summary

Introduction

Laser sources locating at eye-safe 2 μm region, especially for operation wavelengths in the atmospheric transmission window between 2.05 μm and 2.3 μm, have many significant applications in atmospheric lidar measurement [1], remote sensing [2], medical surgery [3,4,5], etc. By using a fiberized grating-based tunable filter, Li et al reported a tunable Tm3+doped fiber laser, core pumped by 1550 nm diodes, operating at a wide spectrum from 1820 nm to 2075 nm with a maximum power of 30 mW and slope efficiency of 27% at 1930 nm [17]. D. Jackson et al employed a Tm3+/Ho3+-codoped silica fiber to demonstrate a 793 nm diode pumped high power fiber laser operating at wavelength near 2105 nm with a slope efficiency of 42% [8]. Hemming et al reported a 790 nm diode pumped tunable Tm3+/Ho3+-codoped aluminosilicate fiber laser by using a diffraction grating, which achieved a wide spectrum operation from ~1850 nm to ~2150 nm with a maximum slope efficiency of 25% at 2040 nm [21]. A six wavelengths switchable laser from 1925 nm and 2200 nm was achieved by employing an FBG array in the cavity

ASE source

Wavelength selectable range based on FBGs

Wavelength switchable operation based on an FBG array

Findings

Conclusion