Abstract

We report a special modulation of refractive index design for obtaining long period fiber grating (LPFG) with a broad-band and top flattened transmission spectrum. The LPFG with modulation envelope of refractive index like Gaussian function was fabricated by high frequency CO2 laser pulses in this paper, and the experimental results showed that the top rejection bandwidth was up to 10nm and the top flatness was less than 0.5dB, which will have potential applications in optical communications, such as polarization-dependent loss compensators, band selection filters, course wavelength division multiplexers and so on.

© 2006 Optical Society of America