We successfully demonstrate a blue diode-pumped green single-wavelength self-Q-switched Ho 3+ :ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF (Ho:ZBLAN) all-fiber laser emitting at ~550 nm. Such a green laser, ...being a very simple device, consists of a 15-cm-long Ho:ZBLAN fiber and a pair of fiber input/output mirrors. The Ho:ZBLAN fiber not only acts as a gain medium but also works as a saturable absorber (SA). The modulation mechanism is induced by the ground-state reabsorption effect in an ineffectively pumped section of the active fiber. Stable Q-switching pulses are characterized by a 889 ns of minimum pulse duration and a 264 nJ of maximum energy pulse at a repetition rate of 67.25 kHz. We believe that this work could provide an appreciable alternative for next generation of pulsed green laser source, which finds the applications in the medical diagnosis, optical imaging, and industrial manufacturing.
We experimentally and theoretically demonstrate a new method to obtain a single-mode operation in long cavity lasers. The method is based on suppressing non-lasing modes in the time domain by ...attenuating their intensity beating with the lasing mode. This suppression is implemented in our experiments by adding into the cavity an intensity modulator, which is controlled by the photo-detected beating signal. We have demonstrated the method in a long Erbium-doped fiber ring laser with a ring cavity length of about 13 m. Single-mode operation without mode-hopping was obtained for a long time duration of about 100 minutes. Although Erbium-doped fiber amplifiers are homogeneously broadened at room temperature, a single-mode operation was achieved in several cavity modes, which do not have the highest small-signal gain. A theoretical model, based on a small-signal stability analysis, is given. The model indicates that the control delay should be accurately chosen.
One of the efficient techniques to enhance the sensitivity of optical fiber sensor is to utilize Vernier effect. However, the complex system structure, precisely controlled device fabrication, or ...expensive materials required for implementing the technique creates the difficulties for practical applications. Here, we propose a highly sensitive optical fiber strain sensor based on two cascaded Fabry-Perot interferometers and Vernier effect. Of the two interferometers, one is for sensing and the other for referencing, and they are formed by two pairs of in-fiber reflection mirrors fabricated by femtosecond laser pulse illumination to induce refractive-index-modified area in the fiber core. A relatively large distance between the two Fabry-Perot interferometers needs to be used to ensure the independent operation of the two interferometers. The fabrication of the device is simple, and the cavity's length can be precisely controlled by a computer-controlled three-dimensional micromachining platform. Moreover, as the device is based on the inner structure inside the optical fiber, good robustness of the device can be guaranteed. The experimental results obtained show that the strain sensitivity of the device is ~28.11 pm/με, while the temperature sensitivity achieved is ~278.48 pm/°C.
•Self-starting harmonically mode-locked (HML) Er-doped fiber laser is presented.•HML is provided by combination of two main factors.•These factors are frequency-shifting and nonlinear polarization ...evolution.•Tunable band pass filter allows to get a pulse repetition rate up to 12 GHz.
We experimentally demonstrate a harmonically mode-locked Er-doped fiber laser. The distinctive feature of the laser is highly stable pulse trains generated via self-starting hybrid mode-locking triggered by frequency-shifting and nonlinear polarization evolution. A intra-cavity tunable bandpass filter allows getting a pulse repetition rate up to 12 GHz with local adjustment of the wavelength.
•Passively mode-locked fiber laser.•Time-stretch dispersion Fourier transform.•Internal dynamics and temporal distributions of tri-pulse structures.•Polarization and gain control.•Manipulation ...mechanism on internal dynamics.
Self-assembly of ultrashort pulses highlights the complex patterns of dissipative solitons, termed soliton molecules in consideration of the particle-like behaviors. Multi-constituent temporal patterns release the degrees of freedom of versatile internal motions, emphasizing the molecular-analogous soliton dynamics and the advanced laser applications. Beyond previous studies, exploring the artificial manipulation of the intra-molecular dynamics would spread a new research horizon of ultrafast science. Here, we report the research on the manipulation mechanism on the internal dynamics under a tri-soliton model via the implementation of the polarization and gain control. Assisted with real-time spectral interferometry, both the binding separations and the relative phases are retrieved to unfold the intra-molecular dynamics of soliton triplets. Particularly, we present the switching among tri-soliton states identified by different binding separations and phase-evolving velocities, and further unveil the universal rules of the internal dynamics. All these findings provide an evident manifestation of the artificial manipulation on the temporal distributions and intra-molecular dynamics, as well as enable promising access to rapid multi-pulse reconfiguration applicable to fiber laser platforms.
We reported on the observation of versatile multi-soliton patterns in an erbium-doped fiber laser with a microfiber-based topological insulator (TI) photonic device. Taking advantage of both the high ...third-order nonlinear susceptibility and excellent saturable absorption of TI, various multi-soliton formations, such as soliton molecules, bound solitons, and soliton rains could be easily obtained at a low pump power. These results might deepen the understanding of nonlinear dynamics of multi-soliton patterns, and further demonstrate that the TI deposited microfiber could operate as a high-performance photonic device with both highly nonlinear effect and saturable absorption for the related optics applications.
•High concentration YDF is used in fiber laser around 1 μm.•Tunable and switchable single- and dual-wavelength YDFL is achieved.•Tunable range for single-wavelength regimes is 17.9 nm.•Maximum ...tunable range for dual-wavelength regimes is 12 nm.
A tunable dual-wavelength ytterbium-doped fiber ring laser based on Sagnac interferometer is proposed and experimentally demonstrated. Due to a broad gain bandwidth of ytterbium-doped fiber, a tuning range of 17.9 nm for single-wavelength lasing output and 8.4 nm for dual-wavelength lasing have been achieved with side-mode suppression ratio higher than 38 dB. In addition, experimental results indicate that the lasing output has favorable wavelength and power stability with the maximum wavelength shift and the peak power fluctuation less than 0.06 nm and 0.94 dB, respectively. Such a wide tunable ytterbium-doped fiber ring laser around the wavelength of 1 µm with simple structure has potential applications in metrology, medical treatments or laser cooling, where the laser wavelength need adjusted accurately.
