Dispersion compensation apparatus
View Patent ↗A dispersion compensation apparatus providing both coarse and fine dispersion compensation employing a pair of slab waveguides, a grating interconnecting the two waveguides, a mirror disposed within the second slab waveguide and one or more thermooptic lense(s), positioned between the mirror and the grating.
1. An optical apparatus comprising:
a first slab waveguide;
a second slab waveguide; and
a grating, optically interconnecting the first slab waveguide with the second slab waveguide;
CHARACTERIZED IN THAT:
the second slab waveguide includes a mirror, positioned at a focal point of a side of the waveguide opposite the grating and wherein the second slab waveguide includes at least two thermooptic lenses interposed between the mirror and the grating, one providing positive (+) dispersion compensation, the second providing negative (−) dispersion compensation.
2. The optical apparatus of claim 1 , wherein the first slab waveguide includes an input/output waveguide, positioned on a side of the slab waveguide opposite the grating.
3. The optical apparatus of claim 1 wherein the grating includes a number of waveguides of predetermined unequal length.
4. The optical apparatus of claim 1 wherein the mirror is flat.
5. The optical apparatus of claim 1 wherein a half-wave plate is inserted in the center of the grating.
6. The optical apparatus of claim 1 wherein a quarter-wave plate is inserted between the thermooptic lens and the mirror.
7. The optical apparatus of claim 1 , wherein its dispersion when the thermooptic lenses are powered off is −D, and the dispersion range when the thermooptic lenses are powered on is designed to be only within the range −2D to 0.
8. The optical apparatus of claim 1 wherein D is in the range of 1200 to 1600 ps/nm, the amount of dispersion encountered in a typical span in a fiber-optic system.
9. An optical apparatus comprising:
a first slab waveguide;
a second slab waveguide; and
a grating, optically interconnecting the first slab waveguide with the second slab waveguide;
CHARACTERIZED IN THAT:
the second slab waveguide includes a mirror, positioned at a focal point of a side of the waveguide opposite the grating and a thermooptic lens, interposed between the mirror and the grating, wherein its dispersion when the thermooptic lens is powered off is −D, and the dispersion range when the thermooptic lens is powered on is designed to be only within the range −2D to 0.
10. The optical apparatus of claim 9 wherein D is in the range of 1200 to 1600 ps/nm, the amount of dispersion encountered in a typical span in a fiber-optic system.
11. The optical apparatus of claim 9 wherein a half-wave plate is inserted in the center of the grating.
12. The optical apparatus of claim 9 wherein a quarter-wave plate is inserted between the thermooptic lens and the mirror.