Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton.

Zhichao Wu,Songnian Fu,Ping Shum,Kai Jiang,Deming Liu,Huizi Li,Jue Song,Ming Tang

doi:10.1038/srep34844

Abstract

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

Highlights

Scientific applications, such as three-dimensional display[21] and polarization division multiplexing transmission[22]
We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber lasers (TDFLs) based on a combination of carbon nanotube (CNT) and nonlinear polarization rotation (NPR) effect induced by residual polarization dependent loss (PDL) arising in wavelength division multiplexer (WDM)
The CNTs are efficiently deposited in the region of the fiber core due to optimal interaction with radiation propagating in the fiber, while at the same time minimizing the waste of the CNTs during device preparation

Summary

Introduction

Scientific applications, such as three-dimensional display[21] and polarization division multiplexing transmission[22]. Some optical components, especially the wavelength division multiplexer (WDM) may possess a relatively large residual polarization dependent loss (PDL)[23] This PDL gives us an inspiration to induce a controllable NPR effect in a SA-based mode-locked fiber laser. Since the fiber birefringence comes from the deviations of the core shape from circularity, transverse internal stress or residual twist[15], it is desired to observe similar soliton features of thulium-doped fiber lasers (TDFLs) operated at 2μm region In this submission, we experimentally demonstrate switchable temporal soliton generation from a TDFL based on a combination of CNT and NPR effect induced by residual PDL arising in WDM. This switchable operation of vector and scalar solitons may greatly enrich the understanding of soliton dynamics in laser cavities and find applications in a wide variety of optical fields

Results

Discussion

Conclusion