Planar waveguide optical spectrum analyzer using a UV-induced grating

An optical spectrum analyzer is demonstrated using a UV-induced, chirped gr ating on a planar waveguide and a linear detector array. The grating provid es both the dispersion with respect to wavelength and the imaging function. The spectral response has a full-width at half-maximum of 0.15 nm and a ba ndwidth of 7.8 nm, A chirp of -1.75 nm/cm and a 12-cm focal length were use d, The design parameters are discussed in terms of the chirp, focal length and resolution. The wavelength dependence of the optimal chirp limits the r esolution for small focal lengths. For longer focal lengths, the spotsize i s diffraction limited and high resolution can be achieved with minimal fabr ication complexity.