Temperature sensing characteristics of tapered Tm³⁺-doped fiber amplifiers

Abstract

We numerically analyze the temperature response of a tapered Tm 3+ -doped fiber amplifier. The analysis includes a redefinition of the coupled pump and signal propagation equations in order to introduce different longitudinal shapes of the tapered doped fiber and the temperature dependence of the absorption and emission cross sections of the Tm 3+ ions under different pump schemes. It was found that the temperature sensitivity of the normalized amplified signal was 2 × 10 −3 /°C for 1 W of pump power and 3 m of doped fiber length, using a parabolic taper in a co-propagating pump scheme. This sensitivity can be increased by at least 5 times if we adjust the design parameters of the fiber amplifier using fiber lengths shorter than 1 m and pump powers lower than 300 mW. Our results contribute with new information for the development and optimization of tapered fiber amplifiers doped with other rare earths, and novel designs for doped-fiber temperature sensors.

Thermal effects on tapered holmium-doped fiber amplifiers

“…In this context, the taper length required to obtain the power conversion in holmiumdoped fiber amplifiers is lower than these required in other rare-Earth-doped fiber amplifiers. 13,14 Then holmium-doped fiber amplifiers can offer an opportunity to develop more compact temperature fiber sensors. In this sense, further analysis needs to be performed to optimize the temperature sensitivity using different taper ratios and the longitudinal shape of the tapered holmium-doped-fiber by employing more reduced fiber lengths.…”

“…This fact has already been demonstrated in Yb-and Tm-doped fiber amplifiers. [10][11][12][13][14] Thus it is reasonable to expect the similar effects in tapered holmium-doped fibers. However, this issue has not been investigated in detail.…”

Temperature Sensing Characteristics of Tapered Doped Fiber Amplifiers

“…Besides, it is worth to note that n 1 T ðÞ and n 2 T ðÞ depend on f p,s r ðÞdue to their relation with I p and I s intensities. Once the temperature-dependent coupled equations are defined, we proceed to model a tapered Yb-doped fiber amplifier with different longitudinal tapered core shapes and different pump schemes [31] as is shown in Figure 1.…”