Distributed feedback laser having enhanced etch stop features
View Patent ↗In one example embodiment, a DFB laser includes a substrate, an active region positioned above the substrate, and a grating layer positioned above the active region. The grating layer includes a portion that serves as a primary etch stop layer. The DFB laser also includes a secondary etch stop layer located either above or below the grating layer, and a spacer layer interposed between the grating layer and the active region.
1. A distributed feedback (DFB) laser, comprising:
a substrate;
an active region positioned above the substrate;
a grating layer positioned above the active region, the grating layer including a portion that serves as a primary etch stop layer;
a secondary etch stop layer located below the grating layer so as to be interposed between the grating layer and the active region; and
a spacer layer interposed between the secondary etch stop layer and the active region.
2. The DFB laser as recited in claim 1 , wherein:
the secondary etch stop layer comprises indium gallium arsenide phosphide:
the spacer layer comprises indium phosphide; and
the grating layer comprises indium gallium arsenide phosphide.
3. The DFB laser as recited in claim 1 , wherein a thickness of the spacer layer is at least partly based upon the presence of the secondary etch stop layer.
4. A TOSA comprising:
a housing; and
the DFB laser as recited in claim 1 positioned within the housing.
5. An optical transceiver module comprising:
the TOSA as recited in claim 4 ;
a ROSA; and
a PCB in electrical communication with the TOSA and the ROSA.