Passively mode locked thulium and thulium/holmium doped fiber lasers using MXene Nb2C coated microfiber

Abstract

As a result of the emergence of two-dimensional (2D) materials for various opto-electronics applications, a new class of materials named MXenes have been attracting interests due to their outstanding nonlinear properties. In this work, an MXene niobium carbide (Nb2C) was proposed and demonstrated as a saturable absorber to induce mode-locking in thulium- and thulium/holmium-doped fiber lasers. The Nb2C solution was first prepared using the liquid exfoliation technique, and then deposited onto a microfiber for integration into the laser cavity. Stable mode-locking operation was observed in both laser cavities, where the center wavelengths of the laser were recorded at 1944 nm for the TDFL and 1950 nm for the THDFL. The generated pulses in the TDFL and THDFL had repetition rates of 9.35 and 11.76 MHz respectively, while their corresponding pulse widths were 1.67 and 1.34 ps. Both of the lasers were highly stable, having SNR values of more than 52 dB and showed no major fluctuations when tested for their long-term stabilities. The results demonstrate an excellent performance of the Nb2C as a saturable absorber, offering opportunities to further explore MXenes for future photonics devices.

MXene Saturable Absorbers in Mode‐Locked Fiber Laser

“…Moreover, a 2 𝜇m mode-locked fiber laser was also demonstrated with a holmium-thulium-doped gain fiber and Nb 2 C-based SA. [166] Figure 10. Optical spectrum for a) mode-locked YDFL.…”

“…[ 201 ] The fast SA characteristic is exhibited by Nb 2 C with the relaxation time of 37.4 fs ( τ 1 ) and 710 fs ( τ 2 ) at 567 nm, and 153 fs ( τ 1 ) and 710 fs ( τ 2 ) at 902 nm. [ 202 ] The fast SA has typically higher I sat , that is, 0.92 GW cm −2 for Nb 2 C. [ 170 ] Nevertheless, further investigation on low I sat for Nb 2 C at 0.0011 MW cm −2[ 165 ] and 0.4 MW cm −2[ 166 ] needs to be verified in the future. Here, the α s of the MXenes was also investigated.…”

“…[93,164] Some MXenes such as Nb 2 C nanosheet were synthesized through the LPE method. [165,166] First, 50 mg of Nb 2 C MXene powder was dispersed in 10 mL of IPA solution. Then, the mixture was sonicated at 40% power for 4 h. Next, the undissolved flakes were removed through centrifugation of the sus-pension at 4000 rpm for 10 min, resulting in the homogeneous Nb 2 C MXene nanosheet in IPA solution.…”

“…Moreover, a 2 μm mode‐locked fiber laser was also demonstrated with a holmium‐thulium‐doped gain fiber and Nb 2 C‐based SA. [ 166 ]…”

Generation of mode-locked pulses based on D-shaped fiber with CdTe as a saturable absorber in the C-band region

“…[35][36][37][38][39] One of the common approaches is using saturable absorbers (SAs), which convert continuous wave (CW) output into a pulse train of short pulses through light-matter interactions based on the self-amplitude modulation of light inside the laser cavity. [40][41][42] SAs can be classied as articial or real.…”