We show that the stophyphen;band width of a distributed feedback (DFB) laser with both facets having antireflective coatings is affected by residual facet reflectivity. In the weakly coupled case the stophyphen;band width of a DFB laser with residual facets having a power reflectivity of about 1.0percnt; is narrower than that with no reflective facets. When the residual power reflectivity of the facets is less than 0.01percnt;, the stophyphen;band width is the same as that with no reflective facets. It is therefore essential to consider the effect of reflective facets to evaluate correctly the coupling coefficient.
展开▼
