Dysprosium-Doped Chalcogenide Master Oscillator Power Amplifier (MOPA) for Mid-IR Emission

Abstract

The paper describes the design of a medium infrared fiber laser based on a dysprosium-doped chalcogenide glass Dy <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> : Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">65</sub> . To obtain a high efficiency, the fiber laser is followed by an optical amplifier. The optimized optical source exploits a master oscillator power amplifier (MOPA) configuration. The MOPA pump and signal wavelengths are 1709 and 4384 nm, respectively. Spectroscopic parameters measured on preliminary samples of chalcogenide glasses are taken into account to fulfill realistic simulations. The MOPA emission is maximized by applying a particle swarm optimization approach. For the dysprosium concentration 6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">25</sup> ions/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and the input pump power of 3 W, an output power of 637 mW can be obtained for optical fiber losses close to 1 dB m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . The optimized MOPA configuration allows a laser efficiency larger than 21%. By considering the high beam quality provided by photonic crystal fibers, it is a good candidate for medium infrared light generation whose main applications include, but are not limited to, molecular spectroscopy and environmental monitoring.