红外与激光工程
2023, 52(6): 20230292
红外与激光工程
2023, 52(6): 20230267
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
2 e-mail: jmxu1988@163.com
3 e-mail: zhoupu203@163.com
In past decades, multi-wavelength lasers have attracted much attention due to their wide applications in many fields. In this paper, we demonstrate a multi-wavelength random fiber laser with customizable spectra enabled by an acousto–optic tunable filter. The operating wavelength range can be tuned from 1114.5 to 1132.5 nm with a maximal output power of 5.55 W, and spectral channel tuning can also be realized with a maximal number of five. The effect of gain competition and the interaction between Raman gain and insertion loss are also analyzed. Furthermore, the output spectra can be ordered by radiating appropriate radio frequency signals to the acousto–optic tunable filter. This work may provide a reference for agile shape spectrum generation and promote multi-wavelength random fiber laser practicability in sensing, telecommunications, and precise spectroscopy.
Photonics Research
2023, 11(2): 159
红外与激光工程
2022, 51(1): 20220015
Author Affiliations
Abstract
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha410073, China
The quantum defect (QD) is an important issue that demands prompt attention in high-power fiber lasers. A large QD may aggravate the thermal load in the laser, which would impact the frequency, amplitude noise and mode stability, and threaten the security of the high-power laser system. Here, we propose and demonstrate a cladding-pumped Raman fiber laser (RFL) with QD of less than 1%. Using the Raman gain of the boson peak in a phosphorus-doped fiber to enable the cladding pump, the QD is reduced to as low as 0.78% with a 23.7 W output power. To our knowledge, this is the lowest QD ever reported in a cladding-pumped RFL. Furthermore, the output power can be scaled to 47.7 W with a QD of 1.29%. This work not only offers a preliminary platform for the realization of high-power low-QD fiber lasers, but also proves the great potential of low-QD fiber lasers in power scaling.
cladding pumping low quantum defect phosphorus-doped fiber Raman fiber laser High Power Laser Science and Engineering
2022, 10(2): 020000e8
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
2 e-mail: jmxu1988@163.com
3 e-mail: zhoupu203@163.com
Temporal intensity fluctuation is one of the inherent features of fiber lasers. When utilizing the fiber lasers to pump a random Raman fiber laser (RRFL), the intensity fluctuation transfer from the pump to the random lasing could affect the output performance significantly. In this paper, we comprehensively compared the spectral, temporal, and power characteristics of an RRFL pumped by two different fiber lasers—a temporally unstable fiber oscillator and a temporally stable amplified spontaneous emission (ASE) source. Owing to less impact of the intensity fluctuation transfer, the ASE source-pumped RRFL shows higher maximum output power, higher spectral purity () and optical signal-to-noise ratio (), weaker spectral broadening, and more stable temporal behavior compared to the fiber oscillator-pumped RRFL. Furthermore, based on the temporal-spatial-coupled Raman equations and the generalized nonlinear Schrödinger equations, we numerically revealed the impact of the pump intensity fluctuations on the output characteristics of RRFLs, and found that the temporal walk-off effect played an important role in the dynamics of intensity fluctuation transfer. This work may provide a reference for designing and implementing high-performance RRFLs and promote their practicability in sensing, telecommunications, and high-power applications.
Photonics Research
2022, 10(3): 03000618
Author Affiliations
Abstract
College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073 Changsha, China
Interplay between dispersion and nonlinearity in optical fibers is a fundamental research topic of nonlinear fiber optics. Here we numerically and experimentally investigate an incoherent continuous-wave (CW) optical field propagating in the fiber with normal dispersion, and introduce a distinctive spectral evolution that differs from the previous reports with coherent mode-locked fiber lasers and partially coherent Raman fiber lasers [Nat. Photonics 9, 608 (2015).]. We further reveal that the underlying physical mechanism is attributed to a novel interplay between group-velocity dispersion (GVD), self-phase modulation (SPM) and inverse four-wave mixing (IFWM), in which SPM and GVD are responsible for the first spectral broadening, while the following spectral recompression is due to the GVD-assisted IFWM, and the eventual stationary spectrum is owing to the dominant contribution of GVD effect. We believe this work can not only expand the light propagation in the fiber to a more general case and help advance the physical understanding of light propagation with different statistical properties, but also benefit the applications in sensing, telecommunications and fiber lasers.