Large refractive index modulation based on a BDK-doped step-index PMMA optical fiber for highly reflective Bragg grating inscription

Xuehao Hu, Xiaoyu Yue, Xin Cheng, Shixin Gao, Rui Min, Heng Wang, Hang Qu, Hwa Yaw Tam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)


We experimentally report high reflectivity on the poly(methyl methacrylate) (PMMA)-based polymer optical fiber Bragg gratings by means of a 266 nm pulsed laser and phase mask technique. In the first recipe, fiber Bragg gratings (FBGs) were manufactured with a single pulse up to 3.7 mJ. After post-annealing, a stable refractive index change up to 4.2 × 10−4 was obtained. In the second recipe, FBGs were inscribed by 22 pulses with a lower pulse energy of 1.4 mJ, showing a stable refractive index change of 6.2 × 10−4. Both behaviors may mainly be attributed to the movement of initiating radicals arising from benzyl dimethyl ketal (BDK) under UV irradiation. The high refractive index change in step-index fibers paves the way to tilted FBG manufacturing with large tilt angles potentially for biomedical applications.

Original languageEnglish
Pages (from-to)2864-2867
Number of pages4
JournalOptics Letters
Issue number12
Publication statusPublished - 15 Jun 2021

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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