Y. Yamada, Y. Yabe and S. Komatsu: Narrow Band-Pass Transmission Filter Consisting of Two Fiber Bragg Gratings With Different Periods, Technical Digest, MOC'03 (Tokyo, Japan, 2003), (2003) 320-323.

We developed a narrow bandpass transmission filter by connecting in series two fiber Bragg gratings (FBGs) with slightly different periods. The filter was fabricated by writing two FBGs directly into the core of a single optical fiber. The center wavelengths of the element FBGs are 1549.78nm and 1550.25nm, and their bandwidths are 0.47nm and 0.44nm, respectively. The measured bandwidth (FWHM) of the fabricated band-pass filter is as narrow as 0.04 nm.