Self-starting Mode-locked Laser Research Articles

A 1.0-µm pulsed generation in ytterbium-doped fiber laser with Gadolinium oxide as a saturable absorber

A passively Q-switched and mode-locked laser was successfully demonstrated, the saturable absorber based on Gadolinium oxide was inserted into the ytterbium-doped fiber laser to generate pulses at the 1.0 µm region. By adjusting the pump power of the laser to 146.46 mW, the laser resonator generates a Q-switched pulse at the center wavelength of 1033.84 nm. The maximum achievable pump power of 175.83 mW has produced a 6.93 µs pulse width, 71.43 kHz repetition rate, and 6.23 nJ pulse energy. Later, the incorporation of a 200 m single-mode fiber has triggered a self-started mode-locked laser. The pulse centered at the peak wavelength of 1033.54 nm. The generated pulse was in the range of 146.46 mW to 183.18 mW with a repetition rate of 0.98 MHz. These results proved an outstanding non-linear optical property of Gadolinium oxide, which offers its compatibility with a near-infrared photonics device.

MXene saturable absorber enabled hybrid mode-locking technology: a new routine of advancing femtosecond fiber lasers performance

Abstract MXene is a promising two-dimensional (2D) material that is widely used in electro-photonic devices due to its unique properties. In this contribution, V2CT x , a novel MXene, was employed as a saturable absorber (SA) for hybrid passively mode-locked fiber lasers. An ultra-stable and self-starting mode-locked laser system with low threshold can be achieved using V2CT x nanosheets and nonlinear polarization evolution (NPE). Signal to noise ratio increased 13 dB compared with using only NPE SA. A 72 fs pulse duration is easily achieved from this hybrid mode-locked fiber laser system. To the best of our knowledge, this is the shortest pulse duration generated from the Yb-doped mode-locked fiber lasers using a hybrid or 2D SAs. This study proves that MXene V2CT x nanosheets can be developed as suitable SAs and served as potential advanced ultrafast photonic devices in the future.

A few-picosecond and high-peak-power passively mode-locked erbium-doped fibre laser based on zinc oxide polyvinyl alcohol film saturable absorber

This paper demonstrates a few-picosecond and high-peak-power mode-locked fiber laser, using an erbium-doped fiber as a gain medium and zinc oxide (ZnO) element as a new passively saturable absorber (SA). The ZnO element was synthesized using a seeding solution and amended with a polyvinyl alcohol to form a film. The ZnO has been identified as an ideal SA due to its high nonlinear optical response, high sustainability to damage threshold, and fast recovery time. Self-started mode-locked laser pulses have been generated at a relatively low pump power of 42 mW with a fundamental repetition rate and pulse duration of 3.26 MHz and 2.60 ps, respectively. The proposed laser operates at 1599.5 nm with a 3 dB spectral bandwidth of 1.12 nm. A maximum output power, pulse energy, and peak power of about 6.91 mW, 2.12 nJ, and 0.82 kW, respectively, are obtained at a maximum pump power of 159 mW. From these findings, we confirm that the proposed laser can be viewed as a promising light source in the emerging optical communication system.

Large anomalous-dispersion mode-locked fiber laser based on a chirped fiber Bragg grating pair

A carbon-nanotube mode-locked erbium fiber laser with large net anomalous dispersion is presented. A chirped fiber Bragg grating (CFBG) pair is incorporated to increase the net-cavity anomalous dispersion and soliton splitting threshold. Self-started mode-locked laser produces stable pulses with repetition rate of 9.26 MHz. Laser spectrum is centered at ~1560 nm with 3 dB bandwidth of 0.43 nm. The typical output pulse energy and duration is 0.21 nJ and 8.05 ps, respectively.

Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (Frep) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest Frep was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

Mode-locked Tm,Ho:KLu(WO(4))(2) laser at 2060 nm using InGaSb-based SESAMs.

Passive mode-locking of a Tm,Ho:KLu(WO(4))(2) laser operating at 2060 nm using different designs of InGaAsSb quantum-well based semiconductor saturable absorber mirrors (SESAMs) is demonstrated. The self-starting mode-locked laser delivers pulse durations between 4 and 8 ps at a repetition rate of 93 MHz with maximum average output power of 155 mW. Mode-locking performance of a Tm,Ho:KLu(WO(4))(2) laser is compared for usage of a SESAM to a single-walled carbon nanotube saturable absorber.

Mode-locked fiber lasers based on doped fiber arrays

We designed a new kind of mode-locked fiber laser based on fiber arrays, where the central core is doped. A theoretical model is given for an all-fiber self-starting mode-locked laser based on this kind of doped fiber array. Two different kinds of fiber lasers with negative dispersion and positive dispersion are simulated and discussed. The stable mode-locked pulses are generated from initial noise conditions by the realistic parameters. The process of self-starting mode-locking multipulse transition and the relationship between the energy of the central core and the propagation distance of the pulses are discussed. Finally, we analyze the difference between the averaged mode-locked laser and the discrete mode-locked laser.

Self-starting mode-locked laser with a nonlinear ring resonator

A laser with a ring resonator that incorporates a nonlinear antiresonant loop is proposed and analyzed. With computer simulation it is shown that the mode-locking process is self-starting and that, when the laser is properly designed, gain-bandwidth-limited pulses can be obtained. Passive mode-locked, bistable, and chaotic solutions are found to depend on the design parameters of the model.