Gap FBG and its application in tunable narrow linewidth fibre laser

Yuanhong Yang, Xuejing Liu, Xiaozhe Zhang, Wei Jin, Mingwei Yang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)


A gap fibre Bragg grating (g-FBG) is fabricated by cutting a uniform FBG in the middle to introduce a small air gap between the two sections. Numerical and experimental investigations show that the g-FBG has the characteristics of both a phase shifted FBG and a Fizeau interferometer. The peak transmission wavelength of the g-FBG can be finely tuned by adjusting the air-gap longitudinally or transversely with respect to the fibre central axis. With a g-FBG as tunable intra-cavity filter, a tunable fibre ring laser with a narrow line-width is demonstrated. The wavelength tuning range of the laser is 0.12 nm with an output power flatness better than 0.9 dB. The 3 dB spectral line-width is less than 12 pm and output power is 3.68 dBm.
Original languageEnglish
Pages (from-to)114-118
Number of pages5
JournalOptics and Laser Technology
Publication statusPublished - 1 Jan 2014


  • Bragg grating
  • Fibre ring laser
  • Gap fibre
  • Tunable filter

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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