Moderate-gain Brillouin amplification: An analytical solution below pump threshold

Abstract

Highly accurate closed-form analytical formula, based on the undepleted pump approximation (UPA), is derived for pump, Stokes and the gain of a Brillouin fiber amplifier (BFA) operating in the moderately depleted pump regime. The material loss of the medium, which is a strong effect in optical fibers, is taken into account.To define validity ranges of the solution, the threshold power of BFA is accurately determined. The obtained results are numerically and experimentally validated. The presented analysis can be used to accurately predict the performance of moderate-gain BFAs.

Characterization of high nonlinearity in Brillouin amplification in optical fibers with applications in fiber sensing and photonic logic

“…Expression (8), rewritten in terms of dimensional intensities I 1 z and I 2 z, coincides with the expression for the intensity of the probe wave in [7]. The solution of the system (3) for the intensities (7) and (8) is not complete until an expression for the output intensity Y 1 0 of the CW is determined, which corresponds to the root of the transcendental equation [7], shown in expression (10).…”

“…The more distorted the probe spectrum, the higher its ratio value will be. Depletion of the pump was calculated using expression (7).…”

“…The most common is the undepleted pump approximation (UPA), employed in [7], which imposes the assumption that the pump wave depletion, due to energy transfer between the pump and probe waves, is negligible. The lack of pump wave depletion is a coarse approximation that does not reflect the challenges of fiber sensing techniques.…”

2 km'ye kadar uzunluktaki Brillouin Fiber Kuvvetlendirici kazancının analitik ifadesi

“…It must be noted that, aforementioned applications in Ref. [2][3][4][5] typically require pump powers above SBS threshold and exploits High-Gain and Saturation region. In Fig 6, BFA gain in the Saturation Region is compared with the experimental data.…”

“…also be used to measure strain and temperature [4] which has led to the design of distributed Brillouin sensors (DBS). In these type of sensors, strain and temperature can be measured along the whole fiber length [5]. In the BFA configuration, SBS can be used for efficient narrow band amplification when the Stokes wave is input from the rear (opposite to the pump) end of the fiber.…”