We investigate integrated narrow-bandwidth interference filters for light in the infrared wavelength region around λ = 1550 nm fabricated in channel waveguides in lithium niobate. The filters are based on holographically recorded refractive index Bragg gratings, one grating is thermally fixed. The devices work polarization independent. We measure a peak reflectivity of η ≥ 95 % and a linewidth (FWHM) around 0.1 nm. The peak wavelength of the filters can be tuned by changing the temperature. The fixed grating operates permanently by illumination with incoherent light of a blue LED.
© 1999 Optical Society of AmericaPDF Article