Edge emitting semiconductor laser comprising a plurality of monolithically integrated laser diodes
An edge emitting semiconductor laser containing a plurality of monolithically integrated laser diodes ( 1, 2, 3 ). Each laser diode ( 1, 2, 3 ) contains an active zone ( 11, 12, 13 ), with the active zones ( 11, 12, 13 ) being in each case arranged between waveguide layers ( 6 ), the waveguide layers ( 6 ) in each case adjoining a cladding layer ( 7, 8 ) at a side remote from the active zone ( 11, 12, 13 ). The cladding layers ( 7, 8 ) comprise inner cladding layers ( 7 ), which are arranged above a bottommost active zone ( 11 ) and below a topmost active zone ( 13 ), and outer cladding layers ( 8 ) which are arranged below the bottommost active zone ( 11 ) or above the topmost active zone ( 13 ). The inner cladding layers ( 7 ) have a smaller thickness than the outer cladding layers ( 8 ).
1. An edge emitting semiconductor laser comprising a plurality of monolithically integrated laser diodes, each laser diode containing an active zone,
wherein the active zones are in each case arranged between waveguide layers;
wherein the waveguide layers in each case adjoin a cladding layer at a side remote from the active zone, the cladding layers comprising inner cladding layers, which are arranged above a bottommost active zone and below a topmost active zone, and outer cladding layers, which are arranged below the bottommost active zone or above the topmost active zone; and
wherein the inner cladding layers have a smaller thickness than the outer cladding layers.
2. The edge emitting semiconductor laser as claimed in claim 1 , wherein the inner cladding layers are thinner than the outer cladding layers by at least a factor of 2.
3. The edge emitting semiconductor laser as claimed in claim 2 , wherein the inner cladding layers are thinner than the outer cladding layers by at least a factor of 5.
4. The edge emitting semiconductor laser as claimed in claim 1 , wherein the inner cladding layers each have a thickness of 300 nm or less.
5. The edge emitting semiconductor laser as claimed in claim 4 , wherein the inner cladding layers each have a thickness of 100 nm or less.
6. The edge emitting semiconductor laser as claimed in claim 1 , wherein the inner cladding layers each have a thickness of 10 nm or more.
7. The edge emitting semiconductor laser as claimed in claim 1 , wherein the outer cladding layers each have a thickness of 500 nm or more.
8. The edge emitting semiconductor laser as claimed in claim 7 , wherein the outer cladding layers each have a thickness of 1 μm or more.
9. The edge emitting semiconductor laser as claimed in claim 1 , wherein a number of the monolithically integrated laser diodes is four or more.
10. The edge emitting semiconductor laser as claimed in claim 1 , wherein the active zones each have a quantum well structure.
11. The edge emitting semiconductor laser as claimed in claim 10 , wherein the quantum well structures of the active zones differ from one another in terms of at least one of their layer thicknesses and their material compositions.
12. The edge emitting semiconductor laser as claimed in claim 11 , wherein the quantum well structures of the of active zones differ from one another in terms of at least one of their layer thicknesses and their material compositions to reduce or entirely compensate for a difference between wavelengths of radiation emitted by the active zones, said difference being brought about by temperature differences of the active zones.
13. The edge emitting semiconductor laser as claimed in claim 1 , wherein said plural monolithically integrated laser diodes are interconnected by tunnel junctions.
14. The edge emitting semiconductor laser as claimed in claim 13 , wherein the tunnel junctions each have a thickness of 40 nm or less.
15. The edge emitting semiconductor laser as claimed in claim 1 , wherein the waveguide layers differ from one another in terms of at least one of their layer thicknesses and their material compositions.