A shallow grating triple-layer guided-mode resonance (GMR) filter and its properties are presented. For this type of GMR filter, the grating layer has the equal refractive index to the waveguide layer. It is shown that the GMR filter with shallow grating has good characteristics of narrow bandwidth, symmetrical line shape, and low-reflection sideband. The spectral FWHM of the GMR filter can be controlled by varying the grating thickness. The desired FWHM at the same resonance wavelength with symmetrical line shape and low-reflection sideband can be obtained by adjusting the grating thickness and the grating period with the total thickness of the grating and waveguide layers kept unchanged.
© 2010 Optical Society of America
Original Manuscript: November 30, 2009
Revised Manuscript: January 20, 2010
Manuscript Accepted: February 2, 2010
Published: March 15, 2010
Wenxing Liu, Zhenquan Lai, Hao Guo, and Ying Liu, "Guided-mode resonance filters with shallow grating," Opt. Lett. 35, 865-867 (2010)