چكيده به لاتين
In this work, thermal problem in graphene-clad microfiber (GCM) generated due to the interaction of laser evanescent field with graphene is studied theoretically. Heat differential equation governs in GCM which is usually applied as a saturable absorber in mode-locked fiber lasers is studied by analytical method. A three-dimensional expression for temperature is presented by considering all of effective parameters in real problem. The results will pave the way for more researches on thermal effects on GCM nonlinearities, self-focusing, thermal phase shift and self-phase modulation. Furthermore, the highest pump power to remain in thermal operational range as well as the thermal damage threshold are presented as the necessary criteria for laser design. Furthermore, the outstanding influence of self- phase modulation (SPM) induced by thermal nonlinear refractive index (TNRI) in graphene-clad microfiber on laser pulse width, during the mode-locking process is demonstrated for the first time. To meet the requirements, analytical relations for effective absorption coefficient of graphene- clad microfiber (GCM), thermal nonlinear refractive index and self-phase-modulation parameter are presented. Improve on pulse compression process by optimizing the GCM parameters such as microfiber diameter and graphene length is studied by the aid of Haus master equation.
