Analysis of transverse mode competition and selection in multicore fiber lasers

We present an analysis of the transverse supermode competition mechanism in multicore fiber lasers based on rate equations extended to fibers with multiple cores. The model is used to analyze 7-core and 19-core fiber lasers with three commonly used feedback mechanisms as boundary conditions: butt-contact mirror or fiber Bragg grating, Talbot cavity, and collimating lens plus mirror. For the two last-named cases, different feedback (reflection) factors for different modes result from the diffraction effect. The diffraction effect favors the inphase supermode. Because of mode mixing, a pure in-phase supermode is not obtained. However, for the 7-core fiber laser the in-phase mode can dominate the output. (c) 2005 Optical Society of America.