Bibliographische Detailangaben
| Titel: |
SEMICONDUCTOR LASER DEVICE, DIFFRACTION GRATING STRUCTURE, AND DIFFRACTION GRATING |
| Document Number: |
20180351328 |
| Publikationsdatum: |
December 6, 2018 |
| Appl. No: |
16/058356 |
| Application Filed: |
August 08, 2018 |
| Abstract: |
A semiconductor laser device is a vernier-type wavelength-tunable semiconductor laser device including an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods. At least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and the intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than the intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Assignees: |
FURUKAWA ELECTRIC CO., LTD. (Tokyo, JP) |
| Claim: |
1. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and an intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than an intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Claim: |
2. The semiconductor laser device according to claim 1, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: |
3. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements is a diffraction grating having a sampled grating structure including a plurality of diffraction grating structures, each of the diffraction grating structure having a structure that is substantially centrosymmetric in a light progressing direction, and has the sampled grating structure having a reflection comb spectrum in which an intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than an intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Claim: |
4. The semiconductor laser device according to claim 3, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: |
5. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements is a diffraction grating of a sampled grating structure including a plurality of diffraction grating structures, a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion are alternately arranged in a predetermined direction in the diffraction grating structure, when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as a basic structure, the diffraction grating structure has a structure formed by omitting at least one of the high-refractive-index portions from the basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure. |
| Claim: |
6. The semiconductor laser device according to claim 5, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: |
7. The semiconductor laser device according to claim 5, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: |
8. The semiconductor laser device according to claim 5, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: |
9. The semiconductor laser device according to claim 8, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: |
10. A semiconductor laser device comprising: a first reflection film; a second reflection film having a higher reflectivity than the first reflection film; an active layer arranged between the first reflection film and the second reflection film; and a diffraction grating provided along the active layer in vicinity of the active layer and having a diffraction grating structure, wherein a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion are alternately arranged in a predetermined direction in the diffraction grating structure, when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as a basic structure, the diffraction grating structure has a structure formed by omitting at least one of the high-refractive-index portions from the basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure, and laser emission is performed in a plurality of longitudinal modes. |
| Claim: |
11. The semiconductor laser device according to claim 10, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: |
12. The semiconductor laser device according to claim 10, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: |
13. The semiconductor laser device according to claim 12, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: |
14. The semiconductor laser device according to claim 10, wherein the diffraction grating is a diffraction grating having a sampled grating structure including a plurality of the diffraction grating structures. |
| Claim: |
15. A diffraction grating structure obtained by alternately arranging a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion in a predetermined direction, wherein when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as the basic structure, the diffraction grating structure has a structure, formed by omitting at least one of the high-refractive-index portions from a basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure. |
| Claim: |
16. The diffraction grating structure according to claim 15, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: |
17. The diffraction grating structure according to claim 15, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: |
18. The diffraction grating structure according to claim 17, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: |
19. A diffraction grating of a sampled grating structure, the diffraction grating comprising the diffraction grating structures according to claim 15. |
| Current International Class: |
01; 01; 01 |
| Dokumentencode: |
edspap.20180351328 |
| Datenbank: |
USPTO Patent Applications |