Tunable optical fiber with compression ring

1. A tunable optical filter, comprising:

a thin film waveguide; and

a discontinuous ring-shaped device substantially surrounding the thin film waveguide;

wherein the ring-shaped device can be mechanically pressed inwardly toward or pulled outwardly away from the thin film waveguide by external radial forces, and a central wavelength of the tunable optical filter can be tuned according to the external radial forces.

2. The tunable optical filter according to claim 1 , wherein the ring-shaped device defines at least one gap therein.

3. The tunable optical filter according to claim 2 , wherein the thin film waveguide comprises a substrate and a multi-layered thin film deposited on the substrate.

4. The tunable optical filter according to claim 3 , wherein the substrate comprises silica-based glass.

5. The tunable optical filter according to claim 3 , wherein the multi-layered thin film comprises high refractive index layers arid low refractive index layers alternately superposed on one another to form the multi-layered structure.

6. The tunable optical filter according to claim 5 , wherein the high refractive index layers comprise tantalum pentoxide.

7. The tunable optical filter according to claim 5 , wherein the low refractive index layers comprise silicon dioxide.

8. The tunable optical filter according to claim 1 , wherein the ring-shaped device is bonded to the thin film waveguide with epoxy or equivalent adhesive material.

9. An optical system comprising:

a tunable optical filter comprising:

a thin film waveguide; and

a discontinuous ring-shaped device substantially surrounding the thin film waveguide; and

output means arranged adjacent the tunable optical filter;

wherein the discontinuous ring-shaped device can be mechanically pressed inwardly toward or pulled outwardly away from the thin film waveguide by external radial forces, and a central wavelength of the tunable optical filter can be tuned according to the external radial forces.

10. The optical system according to claim 9 , wherein the ring-shaped device defines at least one gap therein.

11. The optical system according to claim 10 , wherein the ring-shaped device is bonded to the thin film waveguide with epoxy or equivalent adhesive material.

12. The optical system according to claim 10 , wherein the optical system is a Dense Wavelength Division Multiplexing system.

13. The optical system according to claim 10 , wherein the thin film waveguide comprises a substrate and a multi-layered thin film deposited on the substrate.

14. The optical system according to claim 13 , wherein the substrate comprises silica-based glass.

15. The optical system according to claim 13 , wherein the multi-layered thin film comprises high refractive index layers and low refractive index layers alternately superposed on one another to form the multi-layered structure.

16. The optical system according to claim 15 , wherein the high refractive index layers comprise tantalum pentoxide.

17. The optical system according to claim 15 , wherein the low refractive index layers comprise silicon dioxide.

18. A tunable optical filter comprising:

a thin film waveguide; and

a peripheral discontinuous ring-shaped device substantially encircling the thin film waveguide, said device including a stiff outer device and a soft inner device; wherein

said peripheral device is able to be inwardly or outwardly displaced to generate inward or outward forces upon the thin film waveguide to tune a center wavelength of said filter.

19. The tunable optical filter according to claim 18 , wherein said peripheral device defines at least one gap therein.

20. The tunable optical filter according to claim 18 , wherein outer device defines at least one gap therein.