In this contribution, we present the tandem pumping avenue leveraged performance scaling of random fiber laser to record 3 kW level with inherent temporal stability and near-diffraction-limited beam quality. The high ...In this contribution, we present the tandem pumping avenue leveraged performance scaling of random fiber laser to record 3 kW level with inherent temporal stability and near-diffraction-limited beam quality. The high power system employs a four-stage master oscillator power amplifier chain. The master oscillator is a half-opened cavity structured random distributed feedback fiber laser centered at 1080 nm and pumped by incoherent amplified spontaneous emission source. Narrowband random laser seed is selected by employing a spectral filtering module with a maximum output power of 1.08 W, full width at half maximum linewidth of 0.47 nm and spectral optical-signal-to-noise ratio of about 42 dB. As to the main amplification stage, for given 104 W pre-amplified random laser seed and 3.61 kW pump laser, an ultimate output power of 3.03 kW can be obtained,corresponding to an optical-to-optical conversion efficiency of 81.05%. Nearly single-transverse-mode amplified random laser can be achieved even at full power level for inherent high thermal modal instability threshold enabled by tandem pumping and inducing bending loss for high-order transverse-mode. Further performance scaling of this high power random laser system, such as power boosting, operation wavelength tuning and linewidth alteration, is the next goal.展开更多
The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewi...The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewidth of spontaneous Brillouin scattering remains almost constant when the laser linewidth is less than 1 MHz at the same pulse width; otherwise, it increases sharply. A comparison between a fiber laser （FL） with 4-kHz linewidth at 3 dB and a distributed feedback （DFB） laser with 3-MHz linewidth is made experimentally. When a constant laser power is launched into the sensing fiber, the fitting linewidths of the beat signals （backscattered Brillouin light and local oscillator （LO）） is about 5 MHz wider for the DFB laser than for the FL and the intensity of the beat signal is about a half. Furthermore, the frequency fluctuation in the long sensing fiber is lower for the FL source, yielding about 2 MHz less than that of the DFB laser, indicating higher temperature/strain resolution. The experimental results are in good agreement with the numerical simulations.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61322505 and 61635005)Huo Ying Dong Education Foundation of China(Grant No.151062)the Hunan Provincial Innovation Foundation for Postgraduate Student(Grant No.CX2017B030)
文摘In this contribution, we present the tandem pumping avenue leveraged performance scaling of random fiber laser to record 3 kW level with inherent temporal stability and near-diffraction-limited beam quality. The high power system employs a four-stage master oscillator power amplifier chain. The master oscillator is a half-opened cavity structured random distributed feedback fiber laser centered at 1080 nm and pumped by incoherent amplified spontaneous emission source. Narrowband random laser seed is selected by employing a spectral filtering module with a maximum output power of 1.08 W, full width at half maximum linewidth of 0.47 nm and spectral optical-signal-to-noise ratio of about 42 dB. As to the main amplification stage, for given 104 W pre-amplified random laser seed and 3.61 kW pump laser, an ultimate output power of 3.03 kW can be obtained,corresponding to an optical-to-optical conversion efficiency of 81.05%. Nearly single-transverse-mode amplified random laser can be achieved even at full power level for inherent high thermal modal instability threshold enabled by tandem pumping and inducing bending loss for high-order transverse-mode. Further performance scaling of this high power random laser system, such as power boosting, operation wavelength tuning and linewidth alteration, is the next goal.
基金the National High Technology Research and Development Program of China(Grant No.2012AA041203)the Science and Technology Commission of Shanghai Municipality,China(Grant No.13XD1425400)the Pudong New Area Science and Technology Development Fund,China(Grant No.PKJ2012-D04)
文摘The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewidth of spontaneous Brillouin scattering remains almost constant when the laser linewidth is less than 1 MHz at the same pulse width; otherwise, it increases sharply. A comparison between a fiber laser （FL） with 4-kHz linewidth at 3 dB and a distributed feedback （DFB） laser with 3-MHz linewidth is made experimentally. When a constant laser power is launched into the sensing fiber, the fitting linewidths of the beat signals （backscattered Brillouin light and local oscillator （LO）） is about 5 MHz wider for the DFB laser than for the FL and the intensity of the beat signal is about a half. Furthermore, the frequency fluctuation in the long sensing fiber is lower for the FL source, yielding about 2 MHz less than that of the DFB laser, indicating higher temperature/strain resolution. The experimental results are in good agreement with the numerical simulations.
