Passively Q-switched erbium-doped fiber laser using Fe₃O₄-nanoparticle saturable absorber

Abstract

Received Month X, XXXX; revised Month X, XXXX; accepted Month X, XXXX; posted Month X, XXXX (Doc. ID XXXXX); published Month X, XXXX We experimentally demonstrate a passively Q-switched erbium-doped fiber laser (EDFL) operation by using a saturable absorber based on Fe 3 O 4 nanoparticles (FONP) in magnetic fluid (MF). As a kind of transition metal oxide, the FONP has a large nonlinear optical response with a fast response time for saturable absorber. By depositing MF at the end of optical fiber ferrule, we fabricated a FONP-based saturable absorber, which enables a strong light-matter interaction owing to the confined transmitted optical field within the single mode fiber. Because of large third-order optical nonlinearities of FONP-based saturable absorber, large modulation depth of 8.2% and non saturable absorption of 56.6% are demonstrated. As a result, stable passively Q-switched EDFL pulses with maximum output pulse energy of 23.76 nJ, repetition rate of 33.3 kHz, and pulse width of 3.2 μs are achieved when the input pump power is 110 mW at the wavelength of 980 nm. The laser features a low threshold pump power of ~15 mW.

Q-switched fiber laser based on saturable absorption of ferroferric-oxide nanoparticles

“…Previous work shows that Fe 3 O 4 nanoparticles possess a large third-order optical nonlinearity, semi-conductive property, and size-dependent bandgap [39][40][41][42]. Based on a two-level model for semi-conductive materials [26,46], the nonlinear absorption property can be described as follows: under low incident power, the absorption of such nanoparticles is independent of the laser intensity.…”

“…Recently, several groups have demonstrated that Fe 3 O 4 nanoparticles display a semi-conductive property, and the bandgap can be tuned by controlling their sizes [41]. Such nanoparticles possess a large third-order optical nonlinearity, semi-conductive property, and size-dependent bandgap, which satisfies the saturable absorption condition and thus can be used as a Q-switcher in lasers [42].…”

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

“…For the sake of enhancing power resistance, these SAs have evolved from traditional semiconductor saturable absorber mirrors (SESAMs) [3] to one-dimensional and twodimensional materials, such as carbon nanotubes [4][5][6], graphene [7][8][9][10][11], black phosphorous [12][13][14][15], and transition-metal dichalcogenides (TMDs) [16][17][18][19][20]. Quite recently, it has been demonstrated that another novel material group of zero-dimension transition metal oxides (TMOs) including TiO 2 , ZnO, Al 2 O 3 and Fe 3 O 4 possesses efficient nonlinear SA properties [21][22][23][24][25][26][27][28]. Compared with carbon nanotubes and other two-dimension materials, the prepared zero-dimension nanomaterials-based SA is more uniform due to their smaller lateral size and regular circle-like shape [24][25][26].…”

“…Quite recently, it has been demonstrated that another novel material group of zero-dimension transition metal oxides (TMOs) including TiO 2 , ZnO, Al 2 O 3 and Fe 3 O 4 possesses efficient nonlinear SA properties [21][22][23][24][25][26][27][28]. Compared with carbon nanotubes and other two-dimension materials, the prepared zero-dimension nanomaterials-based SA is more uniform due to their smaller lateral size and regular circle-like shape [24][25][26]. Among the TMOs, Fe 3 O 4 is an attractive nanomaterial due to large third-order nonlinear susceptibility of 4.0 × 10 −10 esu and a high nonlinear optical absorption.…”

“…Besides, Fe 3 O 4 nanoparticles possess semiconductors property, fast response time ranging from 18 to 30 picoseconds and tunable bandgap [24]. In 2016, Bai et al verified the nonlinear optical response characteristic of Fe 3 O 4 nanoparticles and realized a passively Qswitching operation in erbium-doped fiber laser [25]. Subsequently, Mao et al fabricated two filmy Fe 3 O 4 SAs by mixing Fe 3 O 4 nanoparticles into the polyvinyl alcohol solution and polyimide solution to obtain Q-switching operation at 1.55 μm [26].…”