A. A. Latiff

Generation of Mode-Locked Ytterbium Doped Fiber Ring Laser Using Few-Layer Black Phosphorus as a Saturable Absorber

We demonstrate the generation of mode-locked pulses from a double-clad ytterbium-doped fiber laser (YDFL) employing a saturable absorber (SA) made of a few layers of black phosphorus (BP). The BP SA was prepared by mechanically exfoliating BP crystal and spreading the acquired BP flakes on a piece of scotch tape. The tape was then sandwiched between two ferrules and incorporated in a YDFL cavity to achieve a stable mode-locked operation at 1085.58 nm with a repetition rate of 13.5 MHz. A maximum pulse energy of 5.93 nJ was obtained at pump power of 1322 mW with the output power of 80 mW. Our study may well be the first demonstration of the BP-based mode-locked fiber laser that should shed some new insights into two-dimensional layer materials related photonics.

Q-Switched Ytterbium-Doped Fiber Laser Using Black Phosphorus as Saturable Absorber

We demonstrate a Q-switched ytterbium-doped fiber laser (YDFL) using a newly developed multi-layer black phosphorous (BP) saturable absorber (SA). The BP SA is prepared by mechanically exfoliating a BP crystal and sticking the acquired BP flakes onto a scotch tape. A small piece of the tape is then placed between two ferrules and incorporated in a YDFL cavity to achieve a stable Q-switched operation in a 1.0μm region. The laser has a pump threshold of 55.1 mW, a pulse repetition rate that is tunable from 8.2 to 32.9 kHz, and the narrowest pulse width of 10.8 μs. The highest pulse energy of 328 nJ is achieved at the pump power of 97.6mW. Our results show that multi-layer BP is a promising SA for Q-switching laser operation.

Black phosphorus crystal as a saturable absorber for both a Q-switched and mode-locked erbium-doped fiber laser

We report a simple way to generate Q-switched and mode-locked pulses by incorporating black phosphorus (BP) as a saturable absorber (SA) in an erbium-doped fiber laser (EDFL) cavity. The preparation of BP-based SA is facilitated by a mechanical exfoliation method. Stable mode-locked pulses with a repetition rate of 1 MHz and energy of 7.35 nJ energy per pulse are generated under a maximum pump power of 250 mW in the ring cavity.

Ultrafast erbium-doped fiber laser mode-locked with a black phosphorus saturable absorber

We experimentally demonstrate a passive mode-locked erbium-doped fiber laser (EDFL) using a multi-layer black phosphorus saturable absorber (BPSA). The BPSA is fabricated by mechanically exfoliating a BP crystal and sticking the acquired BP flakes onto scotch tape. A small piece of the tape is then placed between two ferrules and integrated into an EDFL cavity to achieve a self-started soliton mode-locked pulse operation at 1560.7 nm wavelength. The 3 dB bandwidth, pulse width, and repetition rate of the laser are 6.4 nm, 570 fs, and 6.88 MHz, respectively. The average output power is 5.1 mW at pump power of 140 mW and thus, the pulse energy and peak power are estimated at 0.74 nJ and 1.22 kW, respectively. The BPSA was constructed in a simple fabrication process and has a modulation depth of 7% to successfully produce the stable mode-locked fiber laser.

Zinc Oxide-Based Q-Switched Erbium-Doped Fiber Laser

We demonstrate a Q-switched erbium-doped fiber laser (EDFL) using a newly developed zinc oxide- (ZnO) based saturable absorber (SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol) film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4 nm with a pump power threshold of 11.8 mW, a pulse repetition rate tunable from 22.79 to 61.43 kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.

Passively Q-switched erbium-doped fibre laser using cobalt oxide nanocubes as a saturable absorber

Abstract We demonstrate a Q-switched Erbium-doped fibre laser (EDFL) utilizing cobalt oxide (Co3O4) nanocubes film based saturable absorber (SA) as a passive Q-switcher. Co3O4 nanocubes are embedded into a polyethylene oxide film to produce a high nonlinear optical response, which is useful for SA application. It has saturation intensity and modulation depth of 3 MW/cm2 and 0.35%, respectively. The proposed laser cavity successfully generates a stable pulse train where the pulse repetition rate is tunable from 29.8 to 70.92 kHz and the pulse-width reduces from 10.9 to 5.02 μs as the 980 nm pump power increases. This result indicates that the Co3O4 is excellent for constructing an SA that can be used in producing a passively Q-switched fibre laser operating at a low pump intensity. To the best of our knowledge, this is the first demonstration of Co3O4 film based fibre laser.

Holmium Oxide Film as a Saturable Absorber for 2μm Q-Switched Fiber Laser

This work reports on the use of the holmium oxide (Ho2 O3) polymer film as a saturable absorber (SA) for generating stable Q-switching pulses operating in a 2-μm region in a thulium-doped fiber laser cavity. The SA is prepared by diluting a commercial Ho2 O3 powder and then mixing it with polyvinyl alcohol (PVA) solution to form a Ho2 O3 -PVA film. A tiny part of the film about 1 mm×1 mm in size is sandwiched between two fiber ferrules with the help of index matching gel. When incorporated in a laser cavity driven by a 1552-nm pump, stable Q-switching pulses are observed at 1955 nm within the pump power range of 363-491 mW. As the pump power increases within this range, the repetition rate rises from 26 kHz to 39 kHz, as the pulse width drops from 4.22 μs to 2.57 μs. The laser operates with a signal-to-noise ratio of 47 dB, and the maximum output power and the pulse energy obtained are 2.67 mW and 69 nJ, respectively. Our results successfully demonstrate that the Ho2 O3 film can be used as a passive SA to generate a 2-μm pulse laser.

Molybdenum Disulphide Tape Saturable Absorber for Mode-Locked Double-Clad Ytterbium-Doped All-Fiber Laser Generation

We demonstrate the generation of passive mode-locked double-clad ytterbium-doped fiber laser operating in a 1-micron region. We prepare the saturable absorber from commercial crystal of molybdenum disulphide (MoS2). Without chemical procedure, the MoS2 is mechanically exfoliated by using a clear scotch tape. A few layers of MoS2 flakes are obtained on the tape. Then, a piece of 1 × 1 mm tape containing MoS2 thin flakes is inserted between two fiber ferrules and is integrated in the ring cavity. Stable mode-locking operation is attained at 1090 nm with a repetition rate of 13.2 MHz. Our mode-locked laser has a maximum output power of 20 mW with 1.48 nJ pulse energy. These results validate that the MoS2 has a broad operating wavelength which covers the 1-micron region, and it is also able to work in a high-power cavity.

Pure antimony film as saturable absorber for Q-switched erbium-doped fiber laser

Abstract This paper reports on the use of Antimony (Sb) polymer film to generate stable Q-switching pulses in Erbium-doped fiber laser (EDFL) cavity. The SA is fabricated by coating a thin layer of Sb on a polyvinyl alcohol (PVA) film through physical vapour deposition (PVD) process. A 1 × 1 mm area of the film SA is cut and integrated into between two fiber ferrules inside the laser cavity for intra-cavity loss modulation. Self-starting and stable Q-switched pulses are obtained within a pump power range from 60 to 142 mW. Within this range, the repetition rate increases from 70.82 to 98.04 kHz, while pulse width decreases from 7.42 to 5.36 μs. The fundamental frequency signal-to-noise ratio of the pulse signal is 74 dB, which indicates the excellent stability of the pulses. The maximum output power and pulse energy are 8.45 mW and 86.19 nJ, respectively. Our demonstration shows that Sb film SA capable of generating stable pulses train operating at 1.55-micron region.

Cadmium Selenide Polymer Microfiber Saturable Absorber for Q-Switched Fiber Laser Applications

We demonstrate the generation of a Q-switching pulse train in an erbium-doped fiber laser (EDFL) cavity using a newly developed cadmium selenide (CdSe) based saturable absorber (SA). The SA is obtained by embedding CdSe nanomaterials into a polymethyl methacrylate (PMMA) microfiber. It is incorporated into an EDFL cavity to generate a Q-switched laser operating at 1533.6 nm. The repetition rates of the produced pulse train are tunable within 37–64 kHz as the pump power is varied from 34 mW to 74 mW. The corresponding pulse width reduces from 7.96 μs to 4.84 μs, and the maximum pulse energy of 1.16 nJ is obtained at the pump power of 74 mW.