WSS with pixel gap compensation
View Patent ↗An optical device compensates for decreased transmission of light caused by gaps between mirrors of a MEMS array. The optical device employs MEMS mirrors having non-reflecting regions on them disposed such that reflecting regions of the MEMS mirrors have substantially the same optical throughput, or an additional optical element having increased transmission at those spatial positions where light impinging on the gaps passes through. Alternatively, the optical device may employ a filter having spectral transmission characteristic with increased transmission at those wavelengths of dispersed light that impinge on the gaps.
1. An optical device comprising:
an array of Micro Electro Mechanical System (MEMS) mirrors, successive ones of said MEMS mirrors having gaps between them, such that said MEMS array shows decreased optical throughput at positions of said gaps; and
an optical element disposed in juxtaposition to said MEMS array, such that light impinging on said MEMS array also traverses said optical element, said optical element having a spatial transmission characteristic which shows increased transmission in at least some positions through which light impinging on said gaps passes, as compared to positions through which light impinging on said MEMS mirrors passes.
2. The optical device according to claim 1 , wherein said optical element compensates for said decreased optical throughput of said MEMS array at said gap positions.
3. The optical device according to claim 1 , wherein said light impinging on said MEMS array is dispersed light such that each position of said spatial transmission characteristic corresponds to a different wavelength of said dispersed light.
4. The optical device according to claim 1 , wherein said optical element comprises a pixelated liquid crystal array having sub-pixels disposed in said positions through which light impinging on said gaps passes, said sub-pixels being biased such that transmission through them is higher than that through other regions of said pixelated liquid crystal array.
5. The optical device according to claim 1 , wherein said optical element comprises a neutral density filter having increased transmission in said positions through which light impinging on said gaps passes.
6. The optical device according to claim 1 , wherein said optical element is disposed in the region of the focal plane of the light traversing a device incorporating said MEMS mirrors.
7. An optical device comprising an array of Micro Electro Mechanical System (MEMS) mirrors, successive ones of said mirrors having gaps between them, wherein said mirrors have non-reflecting regions on them disposed such that reflecting regions of said MEMS mirrors have substantially the same optical throughput.
8. The optical device according to claim 7 , wherein widths of reflecting regions are substantially the same and widths of non-reflecting regions are substantially the same.
9. The optical device according to either of claim 7 , wherein said non-reflecting regions are slots formed in the MEMS mirrors which have widths substantially the same as widths of said gaps.
10. An optical device comprising:
an array of Micro Electro Mechanical System (MEMS) mirrors receiving wavelength dispersed light from an input beam, successive ones of said MEMS mirrors having gaps between them, such that said MEMS array shows decreased optical throughput to the wavelengths of said input beam impinging on said gaps; and
an optical element having a spectral transmission characteristic which shows increased transmission for at least one wavelength of light impinging on one of said gaps, as compared to wavelengths of light impinging on said MEMS mirrors adjacent said one of said gaps.
11. The optical device according to claim 10 , wherein said optical element is disposed in such a position that it is traversed by said input beam before undergoing wavelength dispersion.
12. The optical device according to claim 11 , wherein said optical element is disposed at a fiber level of input to a device incorporating said array of MEMS mirrors.
13. The optical device according to claim 10 , wherein said optical element is at least one etalon.
14. The optical device according to claim 13 , wherein said etalon is either of a Fabry-Perot etalon or a Gires-Tournois etalon.
15. The optical device according to claim 10 , wherein said optical element is a filter that is disposed at an input or output port of an optical apparatus incorporating said optical device.