Realization of the compact static Fourier transform spectrometer LLIFTS in glass integrated optics.

The realization and the characterization of the leaky loop integrated Fourier transform spectrometer (LLIFTS) is described. The principle of the LLIFTS lies on a two-beam interferometer in planar design using a leaky loop waveguide structure. The interference pattern is measured at the edge of the component. The LLIFTS has been realized using the silver/sodium ion exchange on glass substrate technology, which is low cost and requires only a single lithography step. A mask has been designed considering a numerical model recently developed. Interference patterns have been measured in the wavelength range from 1500 to 1630 nm. Wavelength resolutions of 14 and 11 nm have been measured, respectively, on the 350 and the 500 microm radii leaky loop structures on a compact optical device.