title: UV exposure on a single-mode fiber within a multimode interference structure.
abstract: We experimentally study the effects of UV exposure on a single-mode fiber (SMF) with a fiber multimode interferometer (MMI) based on the singlemode-multimode-singlemode-multimode-singlemode (SMSMS) fiber structure. We observe a wavelength shift of over 33 nm when irradiating the central SMF in the SMSMS fiber structure with a 3-mm-width UV beam (the UV laser has a wavelength of 193 nm and pulse energy of 3 mJ). According to our numerical simulation, the SMSMS fiber structure can achieve a very high refractive-index (RI) sensitivity of 67670 nm/RIU with a very good linearity of R2≈0.9999. The structure can find potential application for high-sensitivity RI sensing by replacing the central SMF with a hollow-core optical fiber filled with the sample under test. The UV exposure technique can be used for tuning the characteristics of fiber MMI devices.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.forename: Jinhui
authors.initials: J
authors.lastname: Yuan
authors.forename: Chongxiu
authors.initials: C
authors.lastname: Yu
authors.forename: Xinzhu
authors.initials: X
authors.lastname: Sang
authors.forename: Lipeng
authors.initials: L
authors.lastname: Sun
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Tuan
authors.initials: T
authors.lastname: Guo
authors.forename: Baiou
authors.initials: B
authors.lastname: Guan
authors.forename: Hauping
authors.initials: H
authors.lastname: Chan
authors.forename: Kin Seng
authors.initials: KS
authors.lastname: Chiang
authors.forename: Youqiao
authors.initials: Y
authors.lastname: Ma
authors.forename: Pengfei
authors.initials: P
authors.lastname: Wang
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Semenova
authors.forename: Gerald
authors.initials: G
authors.lastname: Farrell