POLARIZATION-INDEPENDENT FILTERING IN A GRATING-ASSISTED HORIZONTAL DIRECTIONAL COUPLER

We report here on the design and the first realization of a grating-as sisted horizontal directional coupler filter exhibiting a highly reduc ed population sensitivity. The filter, which is based on InP-InGaAsP m aterials, is particularly suitable for integration in a 1.3 +/- 1.3 mu m duplexer. A polarization dependence below 1 dB has been measured fo r the separation of two 10 nm wide channels, respectively centered at 1.28 mu m and 1.32 mu m, for a refection ratio of 10 dB.