Cascaded mode conversion in step-index and graded-index few-mode fibers for tunable bandpass filters

摘要

We present an all-fiber bandpass filter based on stress-induced long-period gratings formed in two few-mode fibers (FMFs) spliced between single-mode fibers. To complete this scheme, we investigate broadband mode conversion in the graded-index FMF and the profile control of intermediary LPn mode.