Photonic integration using a twin waveguide structure
AssigneeThe Trustees of Princeton University
InventorsStephen Forrest, Chih-Ping Chao, Miland Gokhale, Ligeng Xu
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Abstract
A monolithically integrated vertical twin-waveguide structure reduces the sensitivity of the device performance characteristics due to the laser cavity length and variations in the layer structure. This is achieved by the introduction of an absorption or loss layer between the active and passive regions. This layer eliminates the propagation of the even mode, while having minimal effect on the odd mode. The threshold current densities and differential efficiencies of the devices are unaffected by the loss layer. A coupling efficiency of 45% from the laser to the external passive waveguide is obtained.
Claims26
A monolithically integrated device having a twin waveguide structure, comprising:
- an active region for emitting light upon an application of energy;
- a passive region for propagating said light through said device, said passive region coupled to said active region;
- and
- an absorption region for eliminating an even mode of propagation, said absorption region being disposed between said active region and said passive region,
- wherein optical power transfer between said active region and said passive region is achieved over an odd mode of propagation.
A photonic integrated circuit having a twin waveguide structure, wherein optical power is transferred in said twin waveguide structure by propagation of an even mode and an odd mode, said circuit comprising:
- an active element for emitting light upon an application of energy;
- a passive element for propagating said light through said circuit, said passive element coupled to said active element;
- and
- a modal selection element for preventing lasing in said even mode and favoring lasing in said odd mode, such that said optical power is transferred over said odd mode, said modal selection element being disposed in a position corresponding to a zero node of said odd mode.
A monolithically integrated device utilizing a twin waveguide structure on a substrate, said device comprising:
- an active layer for radiating photons in response to an application of energy;
- a passive layer for forwarding said photons through said device, said passive layer overlying said substrate;
- a loss layer for confining a suitable portion of an even mode of propagation in said device, wherein an odd mode of propagation is utilized for optical power transfer between said active layer and said loss layer;
- said active layer being vertically stacked over said passive layer;
- and
- said loss layer being centered between said active layer and said passive layer.
A method for fabricating a photonic integrated device having a twin waveguide structure, comprising the steps of:
- applying a passive layer on a substrate;
- applying a first spacer layer on said passive layer;
- applying an absorption layer on said first spacer layer, said absorption layer prohibiting lasing of an even mode propagating in said device;
- applying a second spacer layer on said absorption layer;
- and
- applying an active layer on said second spacer layer.
Dependencies are inferred from the claim text.