This paper presents the phenomenone of two fiber lasers coherent with each other without active control. The laser arrays
will spontaneously self-organize into in-phase supermode once the conditions are met. In the experiment, the method of
fused-biconical is used. It is significant to utilize evanescent-wave interaction to achieve the in-phase supermode. Only
the adjacent neighbor fiber are closed enough, the interfering pattern can be obtained. Of course, in order to obtain the
interference pattern of the laser output, every procedure must be perfect, such as the distance of the fiber cores, the
tapered slope. Otherwise the coherent pattern will not be achieved. In the paper, according to the coupled theory, the ideal
supermode of the two fiber lasers were analyzed. The intensity distribution of the supermode in the near field and far
field were obtained. In the experiment, the phenomen of two fiber lasers coherent with each other was observed.
comparing with the spectra of the lasers before interaction with each other, the modes of the spectra is diffrent with
spectra before combining, and also is not the simply superposition of the fibers which are pumped individually. Some
modes were restrained, some were promoted, then they are coherent with each other.