IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0210439
(2005-08-23)
|
등록번호 |
US-7359597
(2008-04-15)
|
발명자
/ 주소 |
- Iazikov,Dmitri
- Greiner,Christoph M.
- Mossberg,Thomas W.
|
출원인 / 주소 |
- LightSmyth Technologies Inc
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
14 인용 특허 :
80 |
초록
▼
A planar optical waveguide has a set of diffractive elements and confines propagating optical signals in at least one transverse spatial dimension. Each diffractive element set routes, between input and output ports, a corresponding diffracted portion of an input optical signal propagating in the pl
A planar optical waveguide has a set of diffractive elements and confines propagating optical signals in at least one transverse spatial dimension. Each diffractive element set routes, between input and output ports, a corresponding diffracted portion of an input optical signal propagating in the planar optical waveguide that is diffracted by the diffractive element set. The input optical signal is successively incident on the diffractive elements. A desired level of birefringence for a chosen signal optical transverse mode is determined at least in part by i) selected areal density of diffractive elements, ii) selected diffractive element height and position along the confined transverse spatial dimension, iii) selected thicknesses and indices of materials comprising the diffractive elements, or iv) selected thicknesses and stress-optical coefficients of materials comprising the planar optical waveguide, and selected thermal expansion coefficient differentials among materials comprising the planar optical waveguide or comprising a waveguide substrate thereof.
대표청구항
▼
What is claimed is: 1. An optical apparatus comprising a planar optical waveguide arranged so as to substantially confine in at least one transverse spatial dimension optical signals propagating therein, wherein: the optical signals propagate in the planar optical waveguide in corresponding signal
What is claimed is: 1. An optical apparatus comprising a planar optical waveguide arranged so as to substantially confine in at least one transverse spatial dimension optical signals propagating therein, wherein: the optical signals propagate in the planar optical waveguide in corresponding signal optical transverse modes substantially confined in at least one transverse dimension by the planar optical waveguide; the planar optical waveguide comprises at least one cladding layer and a core, the core consisting of exactly two core layers; and the planar optical waveguide is arranged so as to exhibit a designed level of birefringence for a selected one of the signal optical transverse modes, said arrangement including selected refractive indices and selected relative material volumes of the two core layers that yield the designed level of birefringence. 2. The apparatus of claim 1 wherein said arrangement further includes selected thicknesses and selected stress-optical coefficients of materials comprising the two core layers, and at least one selected non-negligible thermal expansion coefficient differential among the materials comprising those layers or comprising a waveguide substrate thereof, that yield the designed level of birefringence. 3. The apparatus of claim 2 wherein: the two core layers exhibit a selected non-negligible thermal expansion coefficient differential with each other, resulting in differing levels of strain-induced birefringence among them; and said arrangement includes selected thicknesses of the two core layers that yield the designed level of birefringence. 4. The apparatus of claim 2 further comprising a waveguide substrate on which the planar optical waveguide is formed, wherein: each of the two core layers exhibits a corresponding selected thermal expansion coefficient differential with the waveguide substrate, resulting in differing levels of strain-induced birefringence among the two core layers; and said arrangement includes selected thicknesses of the two core layers that yield the designed level of birefringence. 5. The apparatus of claim 2 wherein: the two core layers exhibit a selected non-negligible stress-optical coefficient differential with each other, resulting in differing levels of strain-induced birefringence among them; and said arrangement includes selected thicknesses of the two layers that yield the designed level of birefringence. 6. The apparatus of claim 2 further comprising a waveguide substrate on which the planar optical waveguide is formed, wherein: one of the two core layers exhibits a selected thermal expansion coefficient greater than that of the waveguide substrate; the other one of the two core layers exhibits a selected thermal expansion coefficient less than that of the waveguide substrate; the two core layers exhibit corresponding selected stress-optical coefficients of the same sign; resulting corresponding levels of strain-induced birefringence of the waveguide material layers exhibit opposite signs; and said arrangement includes selected thicknesses of the two core layers that yield the designed level of birefringence. 7. The apparatus of claim 2 wherein the designed level of birefringence is less than a level of birefringence exhibited by a planar optical waveguide comprising only one of the two core layers. 8. The apparatus of claim 2 wherein the designed level of birefringence is at or below an operationally acceptable level. 9. The apparatus of claim 2 wherein the planar optical waveguide comprises a channel waveguide substantially confining in two transverse dimensions optical signals propagating therein, the optical signals propagating in the channel waveguide in corresponding signal optical transverse modes substantially confined in the two transverse dimensions by the channel waveguide. 10. The apparatus of claim 2 wherein the planar optical waveguide comprises a slab waveguide substantially confining in one transverse dimensions optical signals propagating in two dimensions therein, the optical signals propagating in the slab waveguide in corresponding signal optical transverse modes substantially confined in the one transverse dimension by the slab waveguide. 11. The apparatus of claim 2 further comprising a waveguide substrate on which the planar optical waveguide is formed, wherein: at least one of the two core layers comprises doped silica, silicon nitride, or silicon oxynitride; the cladding layer comprises silica or doped silica; and the waveguide substrate comprises silicon or doped silicon. 12. An optical apparatus comprising a planar optical waveguide arranged so as to substantially confine in at least one transverse spatial dimension optical signals propagating therein, wherein: the optical signals propagate in the planar optical waveguide in corresponding signal optical transverse modes substantially confined in at least one transverse dimension by the planar optical waveguide; the planar optical waveguide comprises at least one cladding layer, a first core layer, and a second core layer; the planar optical waveguide is arranged so as to exhibit a designed level of birefringence for a selected one of the signal optical transverse modes, said arrangement including selected refractive indices and selected relative material volumes of the first and second core layers that yield the designed level of birefringence; said arrangement further includes selected thicknesses and selected stress-optical coefficients of materials comprising the first and second core layers, and at least one selected non-negligible thermal expansion coefficient differential among the materials comprising those layers or comprising a waveguide substrate thereof, that yield the designed level of birefringence; the planar optical waveguide further comprises at least one set of diffractive elements; each diffractive element set routes, between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal propagating in the planar optical waveguide that is diffracted by the diffractive element set; the input optical signal is successively incident on the diffractive elements; and said arrangement further includes a selected areal density of diffractive elements that yields the designed level of birefringence. 13. The apparatus of claim 12 wherein said arrangement includes partial-fill-grayscale implementation of the diffractive element set. 14. The apparatus of claim 12 wherein said arrangement includes line-density-grayscale implementation of the diffractive element set. 15. The apparatus of claim 12 wherein said arrangement includes a second diffractive element set overlaid on or interleaved with the at least one diffractive element set to yield the areal density. 16. An optical apparatus comprising a planar optical waveguide arranged so as to substantially confine in at least one transverse spatial dimension optical signals propagating therein, wherein: the optical signals propagate in the planar optical waveguide in corresponding signal optical transverse modes substantially confined in at least one transverse dimension by the planar optical waveguide; the planar optical waveguide comprises at least one cladding layer, a first core layer, and a second core layer; the planar optical waveguide is arranged so as to exhibit a designed level of birefringence for a selected one of the signal optical transverse modes, said arrangement including selected refractive indices and selected relative material volumes of the first and second core layers that yield the designed level of birefringence; said arrangement further includes selected thicknesses and selected stress-optical coefficients of materials comprising the first and second core layers, and at least one selected non-negligible thermal expansion coefficient differential among the materials comprising those layers or comprising a waveguide substrate thereof, that yield the designed level of birefringence; the planar optical waveguide further comprises at least one set of diffractive elements; each diffractive element set routes between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal propagating in the planar optical waveguide that is diffracted by the diffractive element set; and the input optical signal is successively incident on the diffractive elements; and said arrangement further includes a selected diffractive element height and a selected diffractive element position along the confined transverse spatial dimension that yields the designed level of birefringence. 17. The apparatus of claim 16 wherein the diffractive elements of the set are formed at a boundary between the first and second core layers. 18. The apparatus of claim 17 wherein each diffractive element comprises a trench formed in the first core layer and substantially filled with material of the second core layer. 19. The apparatus of claim 16 wherein the diffractive elements of the set are formed at a boundary between one of the core layers and the cladding layer. 20. The apparatus of claim 19 wherein each diffractive element comprises a trench formed in one of the core layers and substantially filled with material of the cladding layer. 21. The apparatus of claim 16 wherein diffractive elements of the set are formed completely within the core layers. 22. The apparatus of claim 16 wherein the diffractive elements of the set extend through only a portion of the thickness of one of the core layers. 23. The apparatus of claim 16 wherein the diffractive elements of the set extend through the entire thickness of at least one of the core layers. 24. The apparatus of claim 2 further comprising a second cladding layer, wherein the two core layers are between the cladding layers. 25. The apparatus of claim 12 wherein the diffractive elements of the set are formed at a boundary between the first and second core layers. 26. The apparatus of claim 12 wherein the diffractive elements of the set are formed at a boundary between one of the core layers and the cladding layer. 27. The apparatus of claim 18 wherein said arrangement further includes a selected trench depth that yields the designed level of birefringence. 28. The apparatus of claim 18 wherein said arrangement further includes a selected trench width that yields the designed level of birefringence. 29. The apparatus of claim 20 wherein said arrangement further includes a selected trench depth that yields the designed level of birefringence. 30. The apparatus of claim 20 wherein said arrangement further includes a selected trench width that yields the designed level of birefringence.
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