Prudenzano F, Mescia L, Palmisano T, Surico M, De Sario M, Righini GC. Optimization of pump absorption in MOF lasers via multi-long-period gratings: design strategies.
APPLIED OPTICS 2012;
51:1420-1430. [PMID:
22441490 DOI:
10.1364/ao.51.001420]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 01/13/2012] [Indexed: 05/31/2023]
Abstract
Different strategies for designing optical couplers, optimized to enhance the pump absorption in the rare-earth-doped core of microstructured fiber lasers, are illustrated. Three kinds/configurations of optical couplers have been designed and compared as examples of the different design strategies which can be followed. Their effectiveness to enhance the performance of an ytterbium-doped, double cladding, microstructured optical fiber laser has been accurately simulated. They consist of a suitable cascade of multiple long-period gratings (MLPGs) inscribed in the fiber core region. The characteristics of the MLPG couplers have been simulated via a homemade computer code based on both rate equations and an extended coupled mode theory. The proposed MLPG couplers seem particularly useful in the case of low rare-earth concentration but, even for a middle-high ytterbium concentration, as N(Yb)=5×10(25) ions/m(3), the slope efficiency S can be increased up to 20%, depending on the fiber length.
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