Passively synchronized Q-switched and mode-locked dual-band Tm3+:ZBLAN fiber lasers using a common graphene saturable absorber

Abstract

Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm3+:ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.5 kHz. For synchronous mode-locked operation, pulses with full-width at half maximum durations of 610 fs and 1.68 ps at wavelengths of 1480 nm and 1845 nm, respectively, are obtained at a repetition rate of 12.3 MHz. These dual-band pulsed sources with an ultra-broadband wavelength separation of ~360 nm will add new capabilities in applications including optical sensing, spectroscopy, and communications.

Recent research and advances of material-based saturable absorber in mode-locked fiber laser

“…In addition, the adjustment of pump power and PC in the laser cavity also generates simultaneous dissipative soliton and soliton pulses at 1923.6 nm and 1997.4 nm, respectively [260]. Moreover, a dual-band MLFL was achieved by sharing gain fiber, Tm 3+ :ZBLAN fiber at the emission wavelength of 1480 nm and 1845 nm [132]. A recent 3 um wavelength with 2865.2 nm centre wavelength [19] and from 2836.2 nm to 2906.2 nm [261] mode-locked Ho 3+ -doped ZBLAN fiber laser was demonstrated with SWCNT-SA.…”

“…A dualband wavelength MLFL is applied in time-resolved and multi-wavelength cavity ringdown spectroscopies, as well as the design of transmitters which operate at two separate operating wavelengths [279]. Based on the dual-band wavelength MLFL in [132], the 1480 nm wavelength is useful for water detection in various liquids, whereas 1845 nm is suitable for laser treatment and surgery for the human retina. In addition, mode-locked laser was employed to write waveguide on glasses [8].…”

A Comparison for Saturable Absorbers: Carbon Nanotube Versus Graphene

“…In the NIR region, a graphene SA was employed in a mode‐locked fiber laser at ≈1, 1.5, and 2 μm. [ 60 ] Besides single‐band lasing, dual‐band simultaneous mode‐locked fiber laser was demonstrated by sharing graphene SA at 1480 and 1845 nm, [ 107 ] and 1565 and 1944. [ 58 ] Apart from the NIR region, graphene SA mirror was also proposed in the mid‐infrared (MIR) region, such as ≈2.4, [ 108 ] ≈2.8, [ 64 ] and ≈4.4 μm.…”

Gold nanoparticle based saturable absorber for Q-switching in 1.5µm laser application

“…In comparison with active Q-switching, passive Q-switching holds more advantages, especially in terms of cost as well as maintaining compactness and flexibility of design [6][7][8]. There are several reports on passive Q-switching techniques such as nonlinear polarization rotation (NPR) [9,10] and saturable absorbers (SAs) such as graphene [11,12] and carbon nanotubes (CNTs), either single-walled [13] or multi-walled [14]. These techniques are practical but many new techniques have also been proposed.…”