An all-fiber high-power Mamyshev oscillator (MO) with only one amplification stage was experimentally demonstrated. The achieved maximum output power was 3.4 W with 77 nJ pulse energy and could be compressed to ~100 fs. By adjusting the pump power, the phenomenon of harmonic mode locking is observed in the experiment, and the highest 5th order harmonic can be achieved, which corresponds to the repetition rate of 44.1 MHz. This compact MO ultrafast laser could operate stably several hours and the power fluctuation within 5 h was less than 0.12%. Such a high power ultrafast laser oscillator could apply a promising source for advanced fabrication, biomedical imaging, micromachining and other practical applications.
An all fiber-based Mamyshev oscillators (MO) is experimentally demonstrated to achieve high energy pulse output. In this high energy MO system, the maximum single pulse energy of 153 nJ was achieved with 1.5 W average power. The pulse width could be externally compressed to < 100 fs by a pair of diffraction gratings. Considering the insertion loss of gratings, the maximum peak power was >1 MW. Meanwhile, this system is verified to have good long-term stability and can run several hours stably. This is the highest record in pulse energy from the all fiber-based ultrafast laser oscillator with picosecond/femtosecond pulse duration, to the best of our knowledge. Such a high energy oscillator could apply a promising source for laser micromachining, advanced fabrication, biomedical imaging, and other practical applications.
A gain-managed nonlinear (GMN) tapered fiber amplifier was experimentally demonstrated. The achieved single pulse energy was 707 nJ and the compressed pulse duration was 67 fs with 10 MW peak power at 1054 nm central wavelength.
Due to the characteristics of easy processing, tunable energy band, and excellent nonlinear optical properties, various novel two-dimensional (2D) materials have been synthesized and employed in ultrafast fiber laser generation. In this work, we demonstrated a stable passively mode-locked operation based on MnPS3 nanosheets as saturable absorber (SA). It is worth mentioning that we have continuously measured the performances of the laser ring cavity for seven days and the results indicated that the mode-locked laser is stable and self-starting. Meanwhile, the maximum output power was 27 mW with the fundamental frequency repetition of 5.102 MHz. These results not only supply other choice of SAs in pulse generation, but also provide a guidance to extend other possible applications of MPT3 family for the nonlinear optics.
In the past decade, two-dimensional (2D) materials have attracted increasing attention due to their energy band structure, optical properties and excellent performance in ultrafast photonics and nonlinear optics. As a kind of new 2D ternary layered material, NiPS3 can exhibit more novel electrical, optical and magnetic properties compared with those unary and binary 2D layered materials because of higher chemical diversity and structural complexity. In this work, we demonstrated a passively Q-switched operation based on few-layer NiPS3 as a saturable absorber (SA) in an erbium-doped fiber (EDF) laser. And the Q-switched output was achieved when the pump power at 40~105 mW. To our best of knowledge, it is the first time to utilize the NiPS3 as a SA in pulse laser generation.
A free-standing black phosphorus saturable absorber (BP-SA) fabricated by a modified electrochemical delamination strategy exfoliation process was inserted inside a Er-doped ring laser cavity. Based on the saturable absorber of BP, a stable pulse laser could be achieved. When the pump power increased to 30 mW, the pulse laser began to initiate. The maximum output power was 4.8 mW. And the repetition rate could vary from 23.24 kHz to 69.65 kHz. The obtained minimum pulse duration is 1.67 μs. These demonstrations indicate that BP could apply in pulse laser field and benefit industrial community in the future.
A black phosphorus saturable absorber (BP-SA) fabricated by a modified electrochemical delamination strategy exfoliation process was inserted inside a Yb-doped ring laser cavity. Based on this BP-SA, a stable nanosecond pulse laser could be achieved. When the pump power increased to 151 mW, a fundamental repetition rate of 6.78 MHz and 3.38 ns pulse began to initiate. The pulse could initiate stably at least 3 hours each day for a week. These demonstrations indicate that the related thin-film BP SA preparation method would make the construction of pulse laser more efficient and benefit industrial community in the future.
KEYWORDS: Phosphorus, Fiber lasers, Pulsed laser operation, Signal to noise ratio, Wavelength division multiplexing, Scanning electron microscopy, Raman spectroscopy, Single mode fibers, Atomic force microscopy
We demonstrated the dark pulse in a Yb-doped fiber laser based on black phosphorus (BP). The dark pulse could be obtained by adjusting intra-cavity polarization state and pump power. The dark pulse operating at fundamental frequency has the high stability with a signal to noise ratio (SNR) of ~53dB. By only adjusting the polarization state in the cavity, the high-order dark pulses were also observed.
A new CFAR (constant false alarm rate) algorithm is proposed for the Blind-CFAR detector which is proposed for CFAR detection in various types of clutter. The new algorithm employs the maximum entropy (MaxEnt) method to estimate the PDF (probability density function) of clutter and thus the CFAR detection thresholds based on the samples of reference cells and some moment constraints. Performance of the new algorithm is proved to converge to the performance of the ideal detector as the numbers of the reference cells and the moment constraints approach to infinity. With finite reference cells and moment constraints, performance of the new algorithm is compared with that of the maximum likelihood (ML) CFAR detector in uniform Weibull clutter with known and mismatched shape parameters. The results show that, the Blind-CFAR detector employing the new algorithm performs as well as the ML-CFAR detector in case of known shape parameters and it outperforms the ML-CFAR detector in case of mismatched shape parameters
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.