Distributed feedback semiconductor laser equipment employing a grating
View Patent ↗The prior art distributed feedback laser having an InGaAlAs active layer involves a problem that its laser characteristics are deteriorated at high temperature due to the high device resistance. According to the present invention, a ridge type laser is fabricated by: forming an InGaAlAs-MQW layer 104 on a n-type InP substrate 101 ; growing a p-type InGaAlAs-GRIN-SCH layer 105 , a p-type InAlAs electron stopping layer 106 and a p-type grating layer 107 in this order on the InGaAlAs-MQW layer 104 ; forming a grating; and regrowing a p-type InP cladding layer 108 and a p-type InGaAs contact layer in this order. The concave depth of the grating is smaller than the thickness of the p-type grating layer 107.
1. An optical semiconductor device comprising:
an InP substrate;
a plurality of layers, stacked on the InP substrate, including a multi-quantum well active layer made of InGaAlAs;
an InAlAs electron stopping layer stacked on the plurality of layers;
an InGaAsP layer including a grating stacked on the InAlAs electron stopping layer; and
an InP cladding layer stacked on the InGaAsP layer;
wherein the grating has alternating concave parts and convex parts, the concave parts having a concave depth terminating in a continuous portion of the grating, such that the concave depth of the grating is smaller than a maximum thickness of the InGaAsP layer.
2. An optical semiconductor device comprising:
an InP substrate;
a plurality of layers, stacked on the InP substrate, including a multi-quantum well active layer made of InGaAlAs;
an InAlAs electron stopping layer stacked on the plurality of layers;
an InGaAsP layer including a grating stacked on the InAlAs electron stopping layer;
an InP spacer layer stacked on the InGaAsP layer;
an InGaAsP etch stopping layer stacked on the InP spacer layer; and
an InP cladding layer stacked on the InGaAsP etch stopping layer;
wherein the grating has alternating concave parts and convex parts, the concave parts having a concave depth terminating in a continuous portion of the grating, such that the concave depth of the grating is smaller than a maximum thickness of the InGaAsP layer.
3. An optical semiconductor device according to claim 2 , wherein the spacer layer comprises an InAlAs layer.
4. An optical semiconductor device according to claim 1 , wherein a composition wavelength of the InGaAsP layer including the grating is not shorter than 1.15 μm and not longer than 1.24 μm.
5. An optical semiconductor device according to claim 2 , wherein a composition wavelength of the InGaAsP layer including the grating is not shorter than 1.15 μm and not longer than 1.24 μm.
6. An optical semiconductor device according to claim 3 , wherein a composition wavelength of the InGaAsP layer including the grating is not shorter than 1.15 μm and not longer than 1.24 μm.
7. An optical semiconductor device according to claim 1 , wherein a portion of the InGaAsP layer including the grating consists of a multi-quantum well layer.
8. An optical semiconductor device according to claim 2 , wherein a portion of the InGaAsP layer including the grating consists of a multi-quantum well layer.
9. An optical semiconductor device according to claim 3 , wherein a portion of the InGaAsP layer including the grating consists of a multi-quantum well layer.
10. An optical semiconductor device according to claim 1 , wherein impurity dopants including at least one of Si and O exist between the InP cladding layer and the InGaAsP layer including the grating.
11. An optical semiconductor device according to claim 2 , wherein impurity dopants including at least one of Si and O exist between the InP spacer layer and the InGaAsP layer including the grating.
12. An optical semiconductor device according to claim 1 , wherein the optical semiconductor device is a ridge type laser in which the InP cladding layer has a shape of a ridge mesa stripe.
13. An optical semiconductor device according to claim 2 , wherein the optical semiconductor device is a ridge type laser in which the InP cladding layer has a shape of a ridge mesa stripe.
14. An optical semiconductor device according to claim 1 , wherein the optical semiconductor device is a buried type laser.
15. An optical semiconductor device according to claim 1 , wherein the optical semiconductor device is an integrated light source in which a laser structure and an electro-absorption modulator are integrated.
16. An optical semiconductor device according to claim 2 , wherein the optical semiconductor device is an integrated light source in which a laser structure and an electro-absorption modulator are integrated.
17. An optical semiconductor device according to claim 13 , wherein the optical semiconductor device is an integrated light source in which a laser structure and an electro-absorption modulator are integrated.
18. An optical semiconductor device according to claim 14 , wherein the optical semiconductor device is an integrated light source in which a laser structure and an electro-absorption modulator are integrated.
19. An optical semiconductor device according to claim 1 , wherein the optical semiconductor device is an integrated light source in which a laser structure and a Mach-Zender modulator are integrated.
20. An optical semiconductor device according to claim 2 , wherein the optical semiconductor device is an integrated light source in which a laser structure and a Mach-Zender modulator are integrated.
21. An optical semiconductor device comprising:
an InP substrate;
a plurality of layers, stacked on the InP substrate, including a multi-quantum well active layer made of InGaAlAs;
an InAlAs electron stopping layer stacked on the plurality of layers;
a group of InGaAsP layers including a grating stacked on the InAlAs electron stopping layer; and
an InP cladding layer stacked on the InGaAsP layer;
wherein the grating has alternating concave parts and convex parts, the concave parts having a concave depth terminating in a continuous portion of the grating, such that the concave depth of the grating is smaller than a maximum thickness of the group of InGaAsP layers.
22. An optical semiconductor device comprising:
an InP substrate;
a plurality of layers, stacked on the InP substrate, including a multi-quantum well active layer made of InGaAlAs;
an InAlAs electron stopping layer stacked on the plurality of layers;
a group of the InGaAsP layers including a grating stacked on the InAlAs electron stopping layer;
an InP spacer layer stacked on the InGaAsP layer;
an InGaAsP etch stopping layer stacked on the InP spacer layer; and
an InP cladding layer stacked on the InGaAsP etch stopping layer;
wherein the grating has alternating concave parts and convex parts, the concave parts having a concave depth terminating in a continuous portion of the grating, such that the concave depth of the grating is smaller than a maximum thickness of the InGaAsP layer.