Thermally fixed reflection gratings for infrared light in LiNbO_3:Ti:Fe channel waveguides

Abstract
We present a narrow-bandwidth interference filter in an optical monomode LiNbO3:Ti:Fe channel waveguide operating in the infrared wavelength region around λ=1.55 µm. The filter consists of a thermally fixed refractive-index Bragg grating recorded with visible green light by use of a holographic technique. In a first approach we measure a reflectivity for the infrared light of 60% and a linewidth (FWHM) of 0.11 nm.