Bi2Te3 Topological Insulator for Domain-Wall Dark Pulse Generation from Thulium-Doped Fiber Laser

Joonhoi Koo,Woojin Shin,Dong Hwan Kim,Nandam Ashok

doi:10.3390/cryst9070337

Joonhoi Koo, Woojin Shin + Show 2 more

Open Access

https://doi.org/10.3390/cryst9070337

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Abstract

We have experimentally demonstrated domain-wall (DW) dark pulses from a thulium-doped fiber laser incorporating a topological insulator saturable absorber (SA). The bulk-structured Bi2Te3 was used as the SA, which was constructed on a fiber ferrule platform through the deposition of the Bi2Te3 mixed with distilled water. The DW dark pulses were generated from the thulium-doped fiber laser cavity with a dual wavelength at 1956 nm and 1958 nm. The dark pulse width and the repetition rate were measured as ~10.3 ns and ~20.7 MHz over the pump power of ~80 mW, respectively. To the best of our knowledge, this work is the first demonstrated generation of the DW dark pulse from a thulium-doped fiber laser using nanomaterial-based SA.

Highlights

Optical soliton has been seen as an attractive physical system for optical communication, optical signal processing system and the formation of an ultra-short pulse within a laser cavity [1,2,3]
By using the Bi2 Te3 topological insulators (TIs) saturable absorber (SA), the DW dark pulse was readily generated from the thulium-doped fiber laser cavity according to the particular polarization state within cavity
The nonlinear transmission of the prepared SA was measured using lab-made, ~1.5 ps fiber laser The withprepared a repetition of 24 MHz at 1.93 μm

Summary

Introduction

Optical soliton has been seen as an attractive physical system for optical communication, optical signal processing system and the formation of an ultra-short pulse within a laser cavity [1,2,3]. It is well known that the formation of DW dark pulses can be more compact compared to CQNLSE-type dark pulses since they can be generated without a highly nonlinear optical medium [16] Such DW dark pulse lasers from fiber lasers have been investigated using nanomaterial-based saturable absorbers (SAs), such as carbon nanotube, topological insulators (TIs) and transition metal dichalcogenides (TMDs) [16,17,18,19,20,21]. The TI, as the new Dirac material, has a unique conducting surface, which is topologically protected against scattering by time-reversal symmetry and insulating energy gaps in bulk [22,23,24] With such a unique physical characteristic, TI has gained huge scientific and Crystals 2019, 9, 337; doi:10.3390/cryst9070337 www.mdpi.com/journal/crystals. Meaningful to investigate the DW dark pulse in the 1950-nm region

TI was chosen a SA work among

Methods

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Results and Discussion

Figure 7a