Thermal Characteristics of an Ytterbium-Doped Fiber Amplifier Operating at 1060 and 1080 nm

Abstract

We experimentally analyze the temperature dependence of an ytterbium-doped fiber amplifier (YDFA) operating at 1060 and 1080 nm, investigating its spectroscopic characteristics and gain properties in the temperature range of 10 to 100 °C. Our measurement indicates that the change in the operating temperature can give rise to a significant effect on the YDFA performance, which also significantly depends on the operating wavelength. At the output power level of approximately 1.5 W, the temperature change from 10 to 100 °C resulted in a signal power drop of approximately 16% at 1060 nm and 5% at 1080 nm, respectively. While this is due mainly to the temperature-dependent spectroscopic characteristics of the gain fiber, it also depends on the input signal and pump power levels. We numerically model this behavior, based on the given experimental conditions and measured fiber parameters. Our numerical results are in good agreement with the experimental results and further suggest that higher seed power to the amplifier should help in minimizing the temperature dependence of the YDFA.

Comparative Experimental Analysis of Thermal Characteristics of Ytterbium-Doped Phosphosilicate and Aluminosilicate Fibers

“…7, a P-based YDF (YDF1/P) was newly fabricated by the modified chemical-vapor deposition and solution doping technique. Its core had a diameter of 6.1 µm and a numerical aperture (NA) of 0.14.…”

“…However, thermal aspects with Yb-doped fibers (YDFs) cannot be simply overlooked if they operate in highpower regimes because their thermal properties are invariably linked to their long-term reliability as well as their overall efficiency [4][5][6][7][8][9][10][11]. For example, the efficiency of an YDF as a gain medium is dependent on the spectroscopy of Yb 3+ ions that changes with temperature [5][6][7], and, in particular, photo-darkening (PD) effects are significantly affected with temperature [8][9][10][11]. Consequently, thermal characteristics, together with nonlinear scattering characteristics, can eventually be limiting factors to the performance of an YDF [12][13].…”

“…Consequently, thermal characteristics, together with nonlinear scattering characteristics, can eventually be limiting factors to the performance of an YDF [12][13]. Thus, they have been intensively investigated from various prospects [4][5][6][7][8][9][10][11]. However, most of the related results have been limited to aluminosilicate (Al)-based YDFs [6,7] since they have predominantly been utilized in many high-power applications [1][2][3].…”

“…Thus, they have been intensively investigated from various prospects [4][5][6][7][8][9][10][11]. However, most of the related results have been limited to aluminosilicate (Al)-based YDFs [6,7] since they have predominantly been utilized in many high-power applications [1][2][3]. One of the reasons must be that they present higher transition cross-sections around the 1-µm region compared to those of YDFs based on other host materials like phosphosilicate [14][15][16] as well as offering relatively low refractive core indices [1].…”

“…Although there were some reports limited to the general spectroscopic characteristics of P-based YDFs [14,16], to the best of our knowledge, there has been no detailed report on their thermal characteristics as gain fibers in high-power regimes. Here, building on our previous investigations [7], we present a comprehensive, comparative experimental analysis on the thermal characteristics of a P-based YDF against an Al-based YDF, including their spectroscopic properties, Stark energy levels, and gain characteristics in a cladding-pumped amplifier configuration. Finally, we discuss all the distinctive thermal characteristics between them.…”