Regular articleHigh power, tunable, ultra-narrowband Yb-doped superfluorescent fiber source operating at wavelength less than 1055 nm with 20 nm tuning range
Introduction
Yb-doped superfluorescent sources (SFSs) have earned a wide variety of applications in low coherence interferometry [1], [2], imaging [3], optical sensors [4] and optical gyroscopes [5] due to high temporal, thermal stability, and short coherence length [6]. Especially, many applications, such as coherent beam combining of phase locked emissions [7], pump source of Raman lasers [8], [9] and spectral beam combination (SBC) [10], require high power narrowband SFSs for their excellent beam quality and maintenance-free operation.
Extensive efforts have been devoted to high power narrowband SFSs in recent years [11], [12], [13], [14]. In 2015, Ma et al demonstrated an 820 W narrowband SFS with center wavelength of 1064.5 nm and full width at half maximum (FWHM) of 0.2 nm [11]. 1.87 kW narrowband SFS with FWHM of 1.7 nm by using fiber circulator and Bragg grating as spectrum filter was reported by Xu et al in 2015 [12]. Besides, there are many reports published on tunable, narrowband SFSs in the past few years. In 2016, Zheng et al generated 1.5 kW narrowband SFS with FWHM of 0.5 nm ranging from 1055.7 nm to 1084.5 nm via combining Bragg gratings and circulators as wavelength selecting components [10]. In 2018, Wu et al also presented the tunable narrowband SFS in the range of 1045–1080 nm, but the output power was only about 30 W and the operating tunable wavelength was longer than 1050 nm [15]. Recently, Gao et al reported a 230 W sub-nm narrowband near-diffraction limited SFS with spectral range from 1052.4 nm to 1072.8 nm based on single-lens spectral filter [16].
As described above, the narrowband SFSs operating above 1055 nm have been extensively investigated. However, compared to the former, the narrowband SFS with operating wavelength less than 1055 nm has incomparable advantages of lower photodarkening [17], [18] and higher threshold on the mode instabilities [19], [20], which have become an alternative source for some applications. Especially for SBC, the high power tunable narrowband SFSs with operating wavelength less than 1055 nm become more and more attractive. On the one hand, the high power tunable narrowband SFSs with operating wavelength less than 1055 nm can extend the spectral region and capacity of narrowband SFSs, and will be useful for further power scaling; on the other hand, the required wavelength shift induced by thermal distortion in the process of high power spectral beam combination can be compensated via the tunability of operating wavelength. Therefore, developing the tunable narrowband SFSs with operating wavelength less than 1055 nm is significantly important for dense spectral beam combination. However, due to spectral broadening effect induced by nonlinear effects, such as stimulated Brillouin scattering, stimulated Raman scattering, and self-phase modulation, it is very difficult to realize the narrowband output and high power simultaneously [21]. In addition, the stronger amplified spontaneous emission (ASE) and reabsorption effect are challenging for achieving high power narrowband output at the at short wavelength region (SWR, referred to wavelength band less than 1060 nm). As a result, the studies on high-power narrowband SFSs with tunable wavelength at SWR are rarely reported.
In this work, a practical solution for achieving a high power, tunable, ultra-narrowband Yb-doped SFS operating wavelength at SWR is proposed theoretically and demonstrated experimentally. The system consists of three components: a broadband SFS, a space-to-fiber tunable spectral filter and a three-stage amplifier chain. Based on rate equations involving temperature, grating monochromator and coupling of Gaussian beam between fibers, the parameters of system are investigated and optimized, and the three characteristics of operating at SWR, tunable and narrowband, and high-power output are completed, respectively. In the experiment, the output power of narrowband SFS operated in tunable range from 1035 nm to 1055 nm exceeds 300 W with M2 factor of 1.47, and the measured FWHM and signal-to-noise ratio (SNR) of which are less than 0.1 nm and beyond 30 dB, respectively. Our results will be beneficial for dense spectral beam combination.
Section snippets
Theoretical model and simulation
The SFS realized in this paper has three characteristics, namely, operating in the shorter emission wavelength of ytterbium ions, tunable and narrowband, and high-power output, which are achieved by all-fiber broadband SFS, a space-to-fiber tunable spectral filter and a three-stage amplifier chain, respectively. Thus, the parameters of these three modules should be optimized.
Experiment setup
The scheme of experimental setup is composed of three parts, a broadband SFS, a space-to-fiber tunable spectral filter and a three-stage amplifier chain, which is depicted in Fig. 4. The backward pumping and single-pass configuration are adopted in the all-fiber broadband SFS. A fiber pigtailed wavelength stabilized laser diode (LD) operating in 976 nm is used as pump source. The pump power is coupled into a 7.0 m Yb-doped active fiber via a signal pump coupler. The core and clad diameters of
Experimental results and discussion
In the experiment, a heat sink is used to control the effect of temperature on active fiber of broadband SFS. The active fiber is coiled orderly on the heat sink and fixed by aluminum foil tape for ensuring the uniformity of thermal conduction. Fig. 5 shows the measured output spectra of SFS at different temperatures of heat sink. It is obviously found when the temperature is decreased from 35 °C to 15 °C, the magnitude at SWR will be higher than that at LWR and also, the central wavelength
Conclusion
In summary, we proposed a high power, tunable, ultra-narrowband SFS operating at wavelength less than 1055 nm. This SFS contains a broadband SFS, a home-mode space-to-fiber tunable spectral filter and a three-stage amplifier chain. Based on the rate equations with temperature, grating monochromator and the coupling theory of Gaussian beam between fibers, the output characteristics of broadband SFS dependence on temperature, the performance of space-to-fiber tunable spectral filter and the
Declaration of Competing Interest
The authors declare that they have no competing financial interests.
Acknowledgements
The authors gratefully acknowledge the Key Research and Development Program Fund of Shaanxi Science and Technology Department (Nos. 2018ZDXM-GY-060, 2018ZDXM-GY-051), National Natural Science Foundation of China (Nos. 61675230, 61875228, 62005310), The Major Basic Research Project of Natural Science Foundation of Shaanxi Province (2017ZDJC-27)
References (28)
- et al.
Optimization investigation for high-power 1034 nm all-fiber narrowband Yb-doped superfluorescent source
Opt. Commun.
(2019) - et al.
30 W all-fiber tunable, narrowband Yb-doped superfluorescent fiber source
Infrared Phys. Technol.
(2018) - et al.
Temperature effects on the emission properties of Yb-doped optical fibers
Opt. Commun.
(2007) - et al.
Number sequence transition method based on MATLAB BVP solvers for high power Yb3+- doped fiber lasers
Opt. Laser Technol.
(2014) - et al.
Optical coherence tomography - principles and applications
Reports Prog. Phys.
(2003) - et al.
Characteristics of a Yb-doped superfluorescent fiber source for use in optical coherence tomography
Opt. Express.
(1998) - et al.
Low-spatial-coherence high-radiance broadband fiber source for speckle free imaging
Opt. Lett.
(2015) - et al.
An economical fiber bragg grating interrogator for medium-scale sensing application
IEEE Photonics Technol. Lett.
(2016) - et al.
Gamma ray effects on double pass backward superfluorescent fiber sources for gyroscope applications
19th Int Conf. Opt. Fibre Sensors.
(2008) - et al.
Exploration in performance scaling and new application avenues of superfluorescent fiber source
IEEE J. Sel. Top. Quantum Electron.
(2018)
Ultra-stable high power mid-infrared optical parametric oscillator pumped by a superfluorescent fiber source
Opt. Express.
Powerful linearly polarized high-order random fiber laser pumped by broadband amplified spontaneous emission source
Sci. Rep.
10.8 kW spectral beam combination of eight all-fiber superfluorescent sources and their dispersion compensation
Opt. Express.
Cited by (7)
Efficient second harmonic generation of a Yb fiber-based amplified stimulated emission source
2022, Optics CommunicationsHydrazone organics with third-order nonlinear optical effect for femtosecond pulse generation and control in the L-band
2022, Optics and Laser TechnologyCitation Excerpt :Many significant advances have been made in recent years of passively mode-locked fiber lasers (PMLFLs) [1–5]. PMLFLs generate ultrashort pulses for a wide range of applications in fiber optic communications, spectroscopy, medicine, and fine processing [6–9]. In addition to practical applications, PMLFLs provide a suitable platform for studying various soliton dynamics and provide a visual platform for the field of nonlinear optics.
2-kW-level superfluorescent fiber source with flexible wavelength and linewidth tunable characteristics
2021, High Power Laser Science and EngineeringBrightness enhancement on random-distributed-feedback Raman fiber lasers pumped by multimode diodes
2024, High Power Laser Science and Engineering1.08 kW Narrowband All-Fiber Super-Fluorescent Source with Spectral-Broadening-Free Property
2021, Zhongguo Jiguang/Chinese Journal of LasersResearch progress of tunable fiber light sources with wavelength near 1 μm
2021, Chinese Optics