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 either above or below the grating layer; and
a spacer layer interposed between the grating 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.
3. The DFB laser as recited in claim 1 , wherein the spacer layer comprises indium phosphide.
4. The DFB laser as recited in claim 1 , wherein the grating layer comprises indium gallium arsenide phosphide.
5. The DFB laser as recited in claim 1 , wherein the secondary etch stop layer has a thickness of about 15 nm, the spacer layer has a thickness of about 5 nm, and the grating layer has a thickness of about 30 nm.
6. The laser as recited in claim 1 , further comprising:
a mode modifier layer positioned above the substrate;
a buffer layer positioned above the mode modifier layer;
a first confinement layer positioned above the buffer layer;
a second confinement layer positioned above the first confinement layer and below the active region;
a third confinement layer positioned above the active region;
a fourth confinement layer positioned above the third confinement layer and below the spacer layer;
a second spacer layer interposed between the spacer layer and the grating layer; and
a mesa layer at least partially positioned above the grating layer.
7. The DFB laser as recited in claim 1 , further comprising:
another secondary etch stop layer positioned either above or below the grating layer; and
a second spacer layer interposed between the grating layer and the second secondary etch stop layer.
8. The DFB laser as recited in claim 1 , wherein the DFB laser is configured for light emission at a wavelength of approximately 1310 nm.
9. A TOSA comprising:
a housing; and
the DFB laser as recited in claim 1 positioned within the housing.
10. An optical transceiver module comprising:
the TOSA as recited in claim 9 ;
a ROSA; and
a PCB in electrical communication with the TOSA and the ROSA.