Switchable dual-wavelength Q-switched fiber laser using multilayer black phosphorus as a saturable absorber

Abstract

Black phosphorus (BP), with thickness-dependent direct energy bandgaps (0.3-2 eV), shows an enhanced nonlinear optical response at near-and mid-infrared wavelengths. In this paper, we present experimentally multilayer BP flakes coated on microfiber (BCM) as a saturable absorber with a modulation depth of 16% and a saturable intensity of 6.8 MW∕cm 2 . After inserting BCM into an Er-doped fiber ring laser, a stable dual-wavelength Q-switched state with central wavelengths of 1542.4 nm and 1543.2 nm (with wavelength spacing as small as 0.8 nm) is obtained with the aid of two cascaded fiber Bragg gratings as a coarse wavelength selector. Moreover, single-wavelength Q-switched operation at 1542.4 nm or 1543.2 nm is also realized, which can be switched between the two wavelengths flexibly just by adjusting the intracavity birefringence. These results suggest that BP combined with the cascaded fiber gratings can provide a simple and feasible candidate for a multiwavelength fiber laser. Our fiber laser may have potential applications in terahertz generation, laser radar, and so on.

Excessively tilted fiber grating based Fe3O4 saturable absorber for passively mode-locked fiber laser

“…When it is switched to orthogonally polarized lights, one peak is almost diminished while the other is fully excited with about 5.6 dB attenuation, indicating 5.6 dB polarization extinction ratio (PER) of the Fe 3 O 4 nanoparticles deposited Ex-TFG. The nonlinear transmission characteristic of this SA device is measured by using typical balanced twin-detector measurement technique [45]. The modulation depth (MD) is measured to be 2.46%, as illustrated in Fig.…”

Passively Mode-Locked Thulium- and Thulium/Holmium-Doped Fiber Lasers Using MXene Nb2C-Coated Microfiber

“…These devices generally cover a wavelength range stretching from the S-band (1460 nm to 1530 nm) [1][2][3] to L-band region (1565 nm to 1625 nm) [4][5][6] . The advancement of optical ber lasers has seen variety of laser output reported in a various laser con guration including pulsed [7][8][9][10][11][12] and multiwavelength [13][14][15][16] . Tremendous achievement in the eld of near-infrared (IR) ber lasers have kept this eld growing to cater the ever-growing demands from laser end-users.…”

Photon-generated carrier transfer process from graphene to quantum dots: optical evidences and ultrafast photonics applications

“…Graphene has previously been demonstrated as an effective saturable absorber (SA) for mode-locked pulse generation due to its ultrabroad absorption spectrum and ultrafast recovery time 13 , but poor operation stability inhibits its practical applications 14,15 . On the other hand, following the demonstration of III-V InGaAs quantum dot (QD) lasers 16 , tremendous progress has been made in high performance active QD laser diodes (LDs) and passive ultra-fast lasers based on QD semiconductor saturable absorber mirrors (SESAMs) [17][18][19][20][21][22][23] .…”