Research On Mode-Selection Of The Coherent Combination On18-cores Photonics Crystal Fiber Lasers Based On Dual-talbot Cavity

The appearance of double-clad fiber laser has provide a potential way to develop thehigh-power fiber lasers. However, with the increasing output power of the fiber laser,some issues embarrassed appears such as nonlinear effects and thermal damagethreshold that it would hamper improving the power of the fiber laser further more.It’s the array designed of several high-power fiber lasers that achieve the coherentcombination to obtain a bunch of lase output stronger. The way has avoided theproblem happened to the single-fiber we mentioned above. Meanwhile the conceptionof the Photonics Crystal Fiber laser(PCF) is just to cater to the coherent combinationthat has drown considerable attentions. We have proposed a newconception——dual-Talbot Cavity, developed from the traditional Talbot Self-ImagePrinciple, to resolve the in-phase mode locking based on the18-cores photonicscrystal fiber. And we have discussed the differences between the two programs.The main work and innovations are summarized as follows:1. We have discussed the program of the phase-locking based on the aperture on thefar-filed distribution. Linked with the multi-slit diffraction and interference theory andfar-field distribution of the in-phase mode, we believed that we should lock thein-phase mode step by step, just like from the multilayer structures to a spot as theoutput of the multi-core PCF. However, it’s impossible to achieve the output that justonly a spot2. The reason why couldn’t lock the in-phase mode in the traditional Talbot cavityis ignorance of the mutual-coupling caused by the end facet of the fiber. We havestudied the phase-locking of the out-of-phase mode by utilizing it. And the conclusionis that the stronger controls to the phase of each core is needed to lock theout-of-phase mode.3. On the basis of the Talbot self-image principle, we have proposed thedual-Talbot cavity and conducted the platform to experiment. Compared with thetraditional program, the dual-Talbot enhance the ability of in-phase mode locking andresolve the problem of mutual coupling between supermodes on the end facet of thefiber. The dual-Talbot program could be seen as the progress came from thesingle-Talbot program. 4. We have discussed the relationships of mode competition and accompanimentbetween different supermodes under the dual-Talbot cavity. We have proved that theout-of-phase mode is existing in the traditional Talbot cavity by grabbing thepopulation inversion, while the Dual-Talbot cavity could suppressed the supermodesthat participated in the mode competition. At the same time, the out-of-phase modeexisting in the output of the dual-Talbot cavity is coming from the mutual-coupling.