title: Frequency-domain modal delay measurement for higher-order mode fiber based on stretched pulse interference.
abstract: We propose and demonstrate a novel modal delay measurement technique for a higher-order mode fiber (HOF) based on optical frequency-domain reflectometry (OFDR) using an extremely simple, entirely passive, and ultrafast wavelength sweeping mechanism, namely, dispersion-induced optical pulse stretching. We obtained a high temporal resolution of approximately 1.12 ps, which was sufficient for discerning the four excited modes in an HOF with a length of only approximately 5 m. The results from our measurements were very consistent with those obtained by using a traditional time-domain measurement method and a conventional OFDR measurement based on a tunable CW laser. Our proposed technique can be also easily adapted to perform conventional time-domain modal delay measurements for very long HOFs.
authors.affiliation: Institut National de la Recherche Scientifique (INRS), Varennes (Montréal) QC J3X 1S2, Canada. ahn@emt.inrs.ca
authors.forename: Tae-Jung
authors.initials: TJ
authors.lastname: Ahn
authors.forename: Yongwoo
authors.initials: Y
authors.lastname: Park
authors.forename: David J
authors.initials: DJ
authors.lastname: Moss
authors.forename: Siddharth
authors.initials: S
authors.lastname: Ramachandran
authors.forename: José
authors.initials: J
authors.lastname: Azaña