scholarly journals Step-Pulse Modulation of Gain-Switched Semiconductor Pulsed Laser

2019 ◽  
Vol 9 (3) ◽  
pp. 602 ◽  
Author(s):  
Bin Li ◽  
Changyan Sun ◽  
Yun Ling ◽  
Heng Zhou ◽  
Kun Qiu
Keyword(s):  
Semiconductor Laser ◽  
Peak Power ◽  
Short Pulse ◽  
Extinction Ratio ◽  
Pulse Signal ◽  
Single Pulse ◽  
Single Mode ◽  
Output Pulse ◽  
Time Domain Reflectometry ◽  
Pulse Modulation

To improve the peak power and extinction ratio and produce ultra-short pulses, a novel approach is presented in this paper offers a highly effective modulated method for a gain-switched semiconductor laser by using step-pulse signal modulation. For the purpose of single pulse output, then the effects on the output from the gain-switched semiconductor laser are studied by simulating single mode rate equation when changing the amplitude and width of the modulated signal. The results show that the proposed method can effectively accelerate the accumulation speed of the population inversion and we can acquire the output pulse with higher peak power and shorter width. Compared with the traditional rectangular wave modulation, this method is advantageous to obtain a high gain switching effect by increasing the second modulation current and reduce the pulse width to saturation at the best working point. It can be incorporated as a practical and cost-effective approach for many fields which need high extinction ratio short pulse, such as the optical time domain reflectometry.

scholarly journals Nonlinearity optimization of dissipative-soliton fiber laser for generation of pulses with 350 kW peak power

2018 ◽  
Vol 6 ◽  
Author(s):  
Han Chi ◽  
Bowen Liu ◽  
Youjian Song ◽  
Minglie Hu ◽  
Lu Chai ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Fiber Length ◽  
Peak Power ◽  
Single Mode ◽  
Output Pulse ◽  
Optimization Method ◽  
Single Mode Fiber ◽  
Dissipative Soliton ◽  
Passive Fiber ◽  
Fiber Segment

We demonstrate a nonlinearity optimization method by altering distribution of passive fibers in a dissipative-soliton mode-locked fiber laser to level up output parameters. In the numerical simulation, we found that the passive fiber segment after gain fiber characterizes the highest average B-integral among fiber segments. By reducing the length of this fiber section and keeping the total passive fiber length as constant, the output pulse energy can be effectively scaled up while maintaining a short dechirped pulse duration, resulting in boosting peak power. With this method, 37-nJ pulses are generated from a dissipative-soliton mode-locked cladding pumped ytterbium-doped single-mode fiber laser in the experiment. The pulse can be dechirped to 66 fs with 350 kW peak power. Moreover, the pulse pedestal is suppressed by a vector-dispersion compressor.

scholarly journals Q-Switched and Mode-Locked Nd/Cr:YAG Ceramic Pulse Laser

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
T. Saiki ◽  
N. Hirota ◽  
S. Kanemori ◽  
Y. Iida
Keyword(s):  
Pulse Laser ◽  
Peak Power ◽  
Short Pulse ◽  
Optical Switch ◽  
Single Mode ◽  
Laser Oscillation ◽  
Pumping Power ◽  
Excite State ◽  
Laser Gain ◽  
Short Pulse Laser

A mode-locked and Q-switched short pulse laser using the Nd3+/Cr3+:YAG ceramic has been constructed with a SESAM and Cr4+:YAG crystal optical switch based on excite state absorption (ESA). Laser oscillations of the pulse laser were observed experimentally. The Nd/Cr:YAG ceramic laser has a high conversion efficiency from white light (such as lamp light or solar light) to the laser. The Nd/Cr:YAG ceramic has a higher laser gain than the Nd:YAG laser for the same pumping power. The laser oscillation can be obtained very easily. A single-mode-locked laser pulse with fast modulation on the order of 100 ps was obtained in some pump power regimes when using the Cr4+:YAG crystal. The obtained pulse duration of the short pulse was a few hundred ps. A maximum peak power of 60 kW was obtained when using a SESAM. The same level of peak power (60 kW) was also obtained when using the Cr4+:YAG crystal.

Laser-Induced Acoustic Waves for Measurement and Imaging

2000 ◽  
Author(s):  
Wen Li ◽  
Ronald A. Roy ◽  
Robin O. Cleveland ◽  
Lawrence J. Berg ◽  
Charles A. DiMarzio
Keyword(s):  
Acoustic Waves ◽  
Peak Power ◽  
Laser Light ◽  
Short Pulse ◽  
Laser Wavelength ◽  
Acoustic Imaging ◽  
Acoustic Energy ◽  
High Peak Power ◽  
First Case ◽  
Very High

Abstract A short pulse of laser light can act as a source of acoustic energy for acoustic imaging. Although there are a number of mechanisms by which the light pulse may generate sound, all require a pulse of high peak power density and short duration. In this work, we address examples where the material is highly absorbing at the laser wavelength, and the sound is generated near the surface. In these cases, there exist two different mechanisms which can convert the light to sound. The first is heating followed by expansion, and the second is generation of a plasma in the air above the surface. In the first case, sound generation occurs in the medium of interest and the energy efficiency can be very high, in the sense that no reflection losses occur. We present two applications from our own research.

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