Low-cost edge-emitting DFB laser arrays for DWDM communication systems implemented by bent and tilted waveguides

This paper emphasizes methodology concerning variations of the emission wavelengths of edge-emitting semiconductor lasers. We present a method based on tilted distibuted feedback (DFB) gratings to be used in combination with specially bent or tilted straight waveguides for the low-cost and ultraprecise definition of different wavelength channels in lasers for Dense wavelength division multiplexing (DWDM) fiberoptic communication systems. The homogeneous DFB grating field is defined using low-cost processes and is tilted with respect to a preferential direction defined by the device borders or the crystal geometry. Our method allows ultraprecise definitions of the DWDM wavelengths and is applicable index- and complex-coupled DFB gratings in both isolated lasers and arrays. Design, technological implementation, and experimental characterization of the devices is presented in this paper. Thin-film heaters are used for correcting small wavelength deviations occurring due to technologically induced tolerances.