All fiber optic hetero-core spliced multimode single mode multimode filter

We report here the transmission characteristics of a step index multimode–single mode–multimode fiber (MSM) optic integrated system. Owing to a good coupling between the fibers, the designed system reveals band-elimination filter characteristics. The variability of the stop-bandwidth for this system is incurred by altering the length and core diameter of the mid-single mode fiber. The observed stop band in the range of 80 nm, having good consistency with numerical results, is found to be dependent on the length of the mid-single mode fiber (SMF). Further, the core diameter of the SMF is also varied to tune the band eliminated output from the proposed MSM structure, which results in a narrow bandwidth of 50 nm, giving a margin of 30 nm with respect to the former. The attained results possess higher potential in the field of optical communications, such as a trimmer, etc.