Toru MIZUNAMI, Hideo KAWASHIMA and Akihiko HAYASHI

Department of Electrical Engineering, Faculty of Engineering, Kyushu Institute of Technology, 1-1 Sensuicho, Tobata, Kitakyushu 804-8550, Japan

(Received May 15, 2002; Accepted July 3, 2002)

We propose a method of tuning resonant wavelengths in the fabrication process of a long-period fiber grating using an amplitude mask tilted relative to the fiber. We irradiated a hydrogenated single-mode fiber with a KrF excimer laser through a tilted amplitude mask with a grating period of 460 μm. Growth of resonant loss peaks in transmission spectra was measured for various tilt angles. A tuning range up to 329 nm was obtained by tilting up to 45^°. The measured results agreed with numerical simulation. It was shown that using only an amplitude mask it is possible to fabricate a long-period fiber grating having resonance at any wavelength throughout the range of 1.2–1.6 μm. A method to determine the tilt angle for a designed wavelength is discussed.

Key words: fiber grating, long-period grating, amplitude mask, wavelength tuning