Add-drop multiplexer with UV-Written Bragg gratings and directional coupler in SiO2-Si integrated waveguides

The needs of wavelength multiplexers is growing up and therefore optical ad d-drop multiplexers (OADMs) become key components for the advanced high bit rate telecommunication networks. Currently, one of the solutions to make O ADM uses fibers Braggs gratings and circulators. In order to take advantage of integrated optics and to avoid the use of expensive circulators, we per form this kind of OADM in ridge silica waveguide on silicon. This technolog y makes possible short based directional coupler (DC) device. In previous w ork, we firstly realized an OADM which involves a symmetrical directional c oupler combined with two Bragg gratings inside the coupling zone. The resul ts meet difficult tradeoff between a high extinction ratio and a narrow spe ctral width of the rejection band. This paper reports some fabrication impr ovements for DC-OADM that lead to more efficient components. Progress resul ts from a lot of works concerning both the photo-writing, process of Bragg gratings and the lowering of the waveguide internal stresses. Thus, we show s that apodization of gratings and low birefringence in the waveguides enab les us to achieve DC-OADM with an extinction ration of 30 dB and a spectral bandwidth less than 1.5 nm.